Examples with solutions for Multiplication of Powers: Calculating powers with negative exponents

Exercise #1

7576=? 7^5\cdot7^{-6}=\text{?}

Video Solution

Step-by-Step Solution

We begin by using the rule for multiplying exponents. (the multiplication between terms with identical bases):

aman=am+n a^m\cdot a^n=a^{m+n} We then apply it to the problem:

7576=75+(6)=756=71 7^5\cdot7^{-6}=7^{5+(-6)}=7^{5-6}=7^{-1} When in a first stage we begin by applying the aforementioned rule and then continue on to simplify the expression in the exponent,

Next, we use the negative exponent rule:

an=1an a^{-n}=\frac{1}{a^n} We apply it to the expression obtained in the previous step:

71=171=17 7^{-1}=\frac{1}{7^1}=\frac{1}{7} We then summarise the solution to the problem: 7576=71=17 7^5\cdot7^{-6}=7^{-1}=\frac{1}{7} Therefore, the correct answer is option B.

Answer

17 \frac{1}{7}

Exercise #2

124126=? 12^4\cdot12^{-6}=\text{?}

Video Solution

Step-by-Step Solution

We begin by using the power rule of exponents; for the multiplication of terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n} We apply it to the given problem:

124126=124+(6)=1246=122 12^4\cdot12^{-6}=12^{4+(-6)}=12^{4-6}=12^{-2} When in a first stage we apply the aforementioned rule and then simplify the subsequent expression in the exponent,

Next, we use the negative exponent rule:

an=1an a^{-n}=\frac{1}{a^n} We apply it to the expression that we obtained in the previous step:

122=1122=1144 12^{-2}=\frac{1}{12^2}=\frac{1}{144} Lastly we summarise the solution to the problem: 124126=122=1144 12^4\cdot12^{-6}=12^{-2} =\frac{1}{144} Therefore, the correct answer is option A.

Answer

1144 \frac{1}{144}

Exercise #3

y2×y7= y^{-2}\times y^7=

Video Solution

Answer

y5 y^5

Exercise #4

Reduce the following equation:

24×22×23= 2^4\times2^{-2}\times2^3=

Video Solution

Answer

242+3 2^{4-2+3}

Exercise #5

Simplify the following equation:

42×44= 4^{-2}\times4^{-4}=

Video Solution

Answer

424 4^{-2-4}

Exercise #6

Simplify the following equation:

34×32= 3^{-4}\times3^{-2}=

Video Solution

Answer

342 3^{-4-2}

Exercise #7

Simplify the following equation:

26×23= 2^6\times2^{-3}=

Video Solution

Answer

263 2^{6-3}

Exercise #8

Insert the corresponding expression:

84×8×81= 8^4\times8\times8^{-1}=

Video Solution

Answer

84+11 8^{4+1-1}

Exercise #9

Insert the corresponding expression:

72×73×75= 7^{-2}\times7^{-3}\times7^5=

Video Solution

Answer

723+5 7^{-2-3+5}

Exercise #10

Reduce the following equation:

52×51×5= 5^{-2}\times5^{-1}\times5=

Video Solution

Answer

52 5^{-2}

Exercise #11

Reduce the following equation:

93×95×92= 9^{-3}\times9^{-5}\times9^{-2}=

Video Solution

Answer

910 9^{-10}

Exercise #12

Reduce the following equation:

10×103×105= 10\times10^{-3}\times10^5=

Video Solution

Answer

103 10^3

Exercise #13

Reduce the following equation:

810×85×84= 8^{-10}\times8^5\times8^4=

Video Solution

Answer

81 8^{-1}

Exercise #14

Reduce the following equation:

32×34= 3^{-2}\times3^4=

Video Solution

Answer

32 3^2

Exercise #15

Reduce the following equation:

53×54= 5^{-3}\times5^{-4}=

Video Solution

Answer

57 5^{-7}

Exercise #16

Reduce the following equation:

67×63= 6^{-7}\times6^3=

Video Solution

Answer

64 6^{-4}

Exercise #17

Insert the corresponding expression:

65×62= 6^{-5}\times6^2=

Video Solution

Answer

163 \frac{1}{6^3}

Exercise #18

Reduce the following equation:

112×115×114= 11^{-2}\times11^{-5}\times11^{-4}=

Video Solution

Answer

11111 \frac{1}{11^{11}}

Exercise #19

Insert the corresponding expression:

91×92×93= 9^{-1}\times9^{-2}\times9^{-3}=

Video Solution

Answer

All answers are correct

Exercise #20

Insert the corresponding expression:

810×85×89= 8^{-10}\times8^{-5}\times8^9=

Video Solution

Answer

186 \frac{1}{8^6}