Evaluate (2/5)^(-2): Negative Exponent Fraction Problem

Question

Insert the corresponding expression:

(25)2= \left(\frac{2}{5}\right)^{-2}=

Video Solution

Solution Steps

00:00 Simplify the following problem
00:04 According to the exponent laws, a fraction raised to a power(-N)
00:08 equals the reciprocal fraction raised to the opposite power (N)
00:12 We will apply this formula to our exercise
00:15 We will invert the fraction
00:19 and proceed to raise it to the opposite power (times(-1))
00:23 This is the solution

Step-by-Step Solution

To solve the problem of converting (25)2\left(\frac{2}{5}\right)^{-2} to positive exponents, we use the rule for negative exponents:

Negative exponent rule states:

  • (ab)n=(ba)n\left(\frac{a}{b}\right)^{-n} = \left(\frac{b}{a}\right)^n — This indicates that we invert the fraction and change the sign of the exponent to positive.

Given expression: (25)2\left(\frac{2}{5}\right)^{-2}.

Application: By using the rule, the negative exponent instructs us to reciprocate the fraction:

(25)2=(52)2\left(\frac{2}{5}\right)^{-2} = \left(\frac{5}{2}\right)^{2}.

The positive exponent (2)(2) indicates the expression is squared. Thus, our action is complete with no further action required.

Thus, the correctly transformed expression of (25)2\left(\frac{2}{5}\right)^{-2} is indeed:

(52)2 \left(\frac{5}{2}\right)^2 .

Answer

(52)2 \left(\frac{5}{2}\right)^2