Simplify the Expression: 7^5 × 7^(-6) Using Laws of Exponents

Question

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

Video Solution

Solution Steps

00:00 Solve
00:02 According to the laws of exponents, any number (A) to the power of (M)
00:05 multiplied by the same number (A) to the power of (N)
00:08 equals the number (A) to the power of (M+N)
00:11 Let's apply this to the problem
00:14 We got the number (7) to the power of (5+(-6))
00:17 Let's calculate this power
00:20 According to the laws of exponents, any number (A) to the power of (-N)
00:23 equals 1 divided by the number (A) to the power of (N)
00:26 Let's apply this to the problem
00:29 We got 1 divided by (7) to the power of (1)
00:32 And this is the solution to the problem

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}