Calculate (4×7)^(-2): Negative Exponent Expression

Question

Insert the corresponding expression:

(4×7)2= \left(4\times7\right)^{-2}=

Video Solution

Solution Steps

00:00 Simplify the following problem
00:03 According to the laws of exponents, when we have a negative exponent
00:08 We can convert to the reciprocal number and obtain a positive exponent
00:11 We will apply this formula to our exercise
00:22 In order to open parentheses of an exponent over a product
00:26 We raise each factor to the power
00:29 We will apply this formula to our exercise
00:35 This is the solution

Step-by-Step Solution


Step 1: We begin by applying the power of a product rule to the expression (4×7)2\left(4 \times 7\right)^{-2}. According to this rule, (ab)n=an×bn(ab)^n = a^n \times b^n. Therefore, we have:

(4×7)2=42×72\left(4 \times 7\right)^{-2} = 4^{-2} \times 7^{-2}

Step 2: Next, we use the negative exponent rule, which states that an=1ana^{-n} = \frac{1}{a^n}. Applying this rule to both parts, we get:

42=1424^{-2} = \frac{1}{4^2} and 72=1727^{-2} = \frac{1}{7^2}

So, 42×72=142×1724^{-2} \times 7^{-2} = \frac{1}{4^2} \times \frac{1}{7^2}

By multiplying these fractions, we obtain:

142×72\frac{1}{4^2 \times 7^2}

Therefore, the solution to the problem is 142×72\frac{1}{4^2 \times 7^2}.

Keep in mind - we could have used the rules in the other way around, first the negative exponent rule, and only then the product rule and the result would still be the same!

Answer

142×72 \frac{1}{4^2\times7^2}