Zero Exponent Rule: Using the laws of exponents

Examples with solutions for Zero Exponent Rule: Using the laws of exponents

Exercise #1

406736490=? \frac{4^0\cdot6^7}{36^4\cdot9^0}=\text{?}

Video Solution

Step-by-Step Solution

First we'll use the fact that raising any number to the power of 0 gives the result 1, mathematically:

X0=1 X^0=1

We'll apply this to both the numerator and denominator of the fraction in the problem:

406736490=1673641=67364 \frac{4^0\cdot6^7}{36^4\cdot9^0}=\frac{1\cdot6^7}{36^4\cdot1}=\frac{6^7}{36^4}

Next we'll note that -36 is a power of the number 6:

36=62 36=6^2

And we'll use this fact in the denominator to get expressions with identical bases in both the numerator and denominator:

67364=67(62)4 \frac{6^7}{36^4}=\frac{6^7}{(6^2)^4}

Now we'll recall the power rule for power of a power to simplify the expression in the denominator:

(am)n=amn (a^m)^n=a^{m\cdot n}

And we'll also recall the power rule for division between terms with identical bases:

aman=amn \frac{a^m}{a^n}=a^{m-n}

We'll apply these two rules to the expression we got above:

67(62)4=67624=6768=678=61 \frac{6^7}{(6^2)^4}=\frac{6^7}{6^{2\cdot4}}=\frac{6^7}{6^8}=6^{7-8}=6^{-1}

Where in the first stage we applied the first rule we mentioned earlier - the power of a power rule and simplified the expression in the exponent of the denominator term, then in the next stage we applied the second power rule mentioned before - the division rule for terms with identical bases, and again simplified the expression in the resulting exponent,

Finally we'll use the power rule for negative exponents:

an=1an a^{-n}=\frac{1}{a^n}

And we'll apply it to the expression we got:

61=16 6^{-1}=\frac{1}{6}

Let's summarize everything we did, we got that:

406736490=16 \frac{4^0\cdot6^7}{36^4\cdot9^0}=\frac{1}{6}

Therefore the correct answer is A.

Answer

16 \frac{1}{6}

Exercise #2

9380=? \frac{9\cdot3}{8^0}=\text{?}

Video Solution

Step-by-Step Solution

We use the formula:

a0=1 a^0=1

9×380=9×31=9×3 \frac{9\times3}{8^0}=\frac{9\times3}{1}=9\times3

We know that:

9=32 9=3^2

Therefore, we obtain:

32×3=32×31 3^2\times3=3^2\times3^1

We use the formula:

am×an=am+n a^m\times a^n=a^{m+n}

32×31=32+1=33 3^2\times3^1=3^{2+1}=3^3

Answer

33 3^3

Exercise #3

454614=? 4^5-4^6\cdot\frac{1}{4}=\text{?}

Video Solution

Step-by-Step Solution

We'll use the law of exponents for negative exponents, but in the opposite direction:

1an=an \frac{1}{a^n} =a^{-n} Let's apply this law to the problem:

454614=454641 4^5-4^6\cdot\frac{1}{4}= 4^5-4^6\cdot4^{-1} When we apply the above law to the second term from the left in the sum, and convert the fraction to a term with a negative exponent,

Next, we'll use the law of exponents for multiplying terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n} Let's apply this law to the expression we got in the last step:

454641=4546+(1)=45461=4545=0 4^5-4^6\cdot4^{-1} =4^5-4^{6+(-1)}=4^5-4^{6-1}=4^5-4^{5}=0 When we apply the above law of exponents to the second term from the left in the expression we got in the last step, then we'll simplify the resulting expression,

Let's summarize the solution steps:

454614=454641=4545=0 4^5-4^6\cdot\frac{1}{4}= 4^5-4^6\cdot4^{-1} =4^5-4^{5}=0

We got that the answer is 0,

Therefore the correct answer is answer A.

Answer

0

Exercise #4

53+5353=? 5^3+5^{-3}\cdot5^3=\text{?}

Video Solution

Step-by-Step Solution

We'll use the power rule for multiplication between terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n} and we'll simplify the second term on the left in the equation using it:
53+5353=53+53+3=53+50=53+1 5^3+5^{-3}\cdot5^3=5^3+5^{-3+3}=5^3+5^0=5^3+1 where in the first stage we applied the mentioned rule to the second term on the left, then we simplified the expression with the exponent, and in the final stage we used the fact that any number raised to the power of 0 equals 1,

We didn't touch the first term of course since it was already simplified,

Therefore the correct answer is answer C.

Answer

53+1 5^3+1

Exercise #5

7483(17)4=? 7^4\cdot8^3\cdot(\frac{1}{7})^4=\text{?}

Video Solution

Step-by-Step Solution

We use the formula:

(ab)n=anbn (\frac{a}{b})^n=\frac{a^n}{b^n}

We decompose the fraction inside of the parentheses:

(17)4=1474 (\frac{1}{7})^4=\frac{1^4}{7^4}

We obtain:

74×83×1474 7^4\times8^3\times\frac{1^4}{7^4}

We simplify the powers: 74 7^4

We obtain:

83×14 8^3\times1^4

Remember that the number 1 in any power is equal to 1, thus we obtain:

83×1=83 8^3\times1=8^3

Answer

83 8^3

Exercise #6

(3)584(3)3(3)2(3)5=? \frac{(-3)^5\cdot8^4}{(-3)^3(-3)^2(-3)^{-5}}=\text{?}

Video Solution

Step-by-Step Solution

First, let's recall the law of exponents for multiplication between terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n}

and we'll use it to handle the fraction's denominator in the problem:

(3)584(3)3(3)2(3)5=(3)584(3)3+2+(5)=(3)584(3)0 \frac{(-3)^5\cdot8^4}{(-3)^3(-3)^2(-3)^{-5}}=\frac{(-3)^5\cdot8^4}{(-3)^{3+2+(-5)}}=\frac{(-3)^5\cdot8^4}{(-3)^0}

where in the first stage we'll apply the above law to the denominator and then simplify the expression with the exponent in the denominator,

Now let's remember that raising any number to the power of 0 gives the result 1, or mathematically:

X0=1 X^0=1

therefore the denominator we got in the last stage is 1,

meaning we got that:

(3)584(3)3(3)2(3)5=(3)584(3)0=(3)5841=(3)584 \frac{(-3)^5\cdot8^4}{(-3)^3(-3)^2(-3)^{-5}}=\frac{(-3)^5\cdot8^4}{(-3)^0}=\frac{(-3)^5\cdot8^4}{1}=(-3)^5\cdot8^4

Now let's recall the law of exponents for an exponent of a product in parentheses:

(xy)n=xnyn (x\cdot y)^n=x^n\cdot y^n

and we'll apply this law to the first term in the product we got:

(3)584=(13)584=(1)53584=13584=3584 (-3)^5\cdot8^4=(-1\cdot3)^5\cdot8^4 =(-1)^5\cdot3^5\cdot8^4=-1\cdot 3^5\cdot 8^4=-3^5\cdot8^4

Note that the exponent applies separately to both the number 3 and its sign, which is the minus sign that is actually multiplication by 1 -1

Let's summarize everything we did, we got that:

(3)584(3)3(3)2(3)5=(3)584=3584 \frac{(-3)^5\cdot8^4}{(-3)^3(-3)^2(-3)^{-5}}=(-3)^5\cdot8^4 = -3^5\cdot8^4

Therefore the correct answer is answer C.

Answer

3584 -3^5\cdot8^4

Exercise #7

3319351932193=? 3^{-3}\cdot\frac{19^{35}\cdot19^{-32}}{19^3}=\text{?}

Video Solution

Step-by-Step Solution

Let's start by simplifying the second term in the complete multiplication, meaning - the fraction. We'll simplify it in two stages:

In the first stage we'll use the power law for multiplication between terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n}

and simplify the fraction's numerator:

19351932193=1935+(32)193=193532193=193193 \frac{19^{35}\cdot19^{-32}}{19^3}=\frac{19^{35+(-32)}}{19^3}=\frac{19^{35-32}}{19^3}=\frac{19^3}{19^3}

Next, we can either remember that dividing any number by itself gives 1, or use the power law for division between terms with identical bases:

aman=amn \frac{a^m}{a^n}=a^{m-n} to get that:193193=1933=190=1 \frac{19^3}{19^3}=19^{3-3}=19^0=1

where in the last step we used the fact that raising any number to the power of 0 gives 1, meaning mathematically that:

X0=1 X^0=1

Let's summarize this part, we got that:

19351932193=1 \frac{19^{35}\cdot19^{-32}}{19^3}=1

Let's now return to the complete expression in the problem and substitute this result in place of the fraction:

3319351932193=331=33 3^{-3}\cdot\frac{19^{35}\cdot19^{-32}}{19^3}=3^{-3}\cdot1=3^{-3}

In the next stage we'll recall the power law for negative exponents:

an=1an a^{-n}=\frac{1}{a^n}

and apply this law to the result we got:

33=133=127 3^{-3}=\frac{1}{3^3}=\frac{1}{27}

Summarizing all the steps above, we got that:

3319351932193=33=127 3^{-3}\cdot\frac{19^{35}\cdot19^{-32}}{19^3}=3^{-3}=\frac{1}{27}

Therefore the correct answer is answer A.

Answer

127 \frac{1}{27}

Exercise #8

53505255= 5^{-3}\cdot5^0\cdot5^2\cdot5^5=

Video Solution

Step-by-Step Solution

We use the power property to multiply terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n} Keep in mind that this property is also valid for several terms in the multiplication and not just for two, for example for the multiplication of three terms with the same base we obtain:

amanak=am+nak=am+n+k a^m\cdot a^n\cdot a^k=a^{m+n}\cdot a^k=a^{m+n+k} When we use the mentioned power property twice, we could also perform the same calculation for four terms of the multiplication of five, etc.,

Let's return to the problem:

Keep in mind that all the terms of the multiplication have the same base, so we will use the previous property:

53505255=53+0+2+5=54 5^{-3}\cdot5^0\cdot5^2\cdot5^5=5^{-3+0+2+5}=5^4 Therefore, the correct answer is option c.

Note:

Keep in mind that 50=1 5^0=1

Answer

54 5^4

Exercise #9

20345492=? \frac{2^0\cdot3^{-4}}{5^4\cdot9^2}=\text{?}

Video Solution

Answer

15438 \frac{1}{5^4\cdot3^8}

Exercise #10

923463=? \frac{9^2\cdot3^{-4}}{6^3}=\text{?}

Video Solution

Answer

63 6^{-3}

Exercise #11

b126(1b)2a=? \sqrt[6]{b^{12}}\cdot(\frac{1}{b})^2\cdot a=\text{?}

Video Solution

Answer

a a