Solve: 3^(-3) × 19^35 × 19^(-32) ÷ 19^3 | Exponent Simplification

Question

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

Video Solution

Solution Steps

00:00 Solve
00:04 When multiplying powers with equal bases
00:08 The power of the result equals the sum of the powers
00:12 We'll use this formula in our exercise, we'll sum the powers
00:33 Any number divided by itself always equals 1
00:40 Any fraction/number with a negative power
00:44 We can flip the numerator and denominator to get a positive power
00:47 We'll use this formula in our exercise
00:53 Let's calculate 3 to the power of 3
00:57 And this is the solution to the question

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}