Question

For what value of y does 125 = (StartFraction 1 Over 25 EndFraction) Superscript y minus 1? Negative five-halves –2 –1 Negative one-half.

Answer 1

Answer:

D. -1/2

Step-by-step explanation:

First to rewrite the equation in numbers

$125=\frac{1}{25}^{y-1}$

First, we need to find what exponent would get 1/25 to 125.

$\frac{1}{25}^{y}=125$

Sense 1/25 is a fraction we must use a negative exponent to make it a whole number. We can just find what exponent would get 25 to 125 then make it negative. 1 wouldn't be enough and 2 would be too much so y is between 1 and 2 into negative is between -1 and -2. Sense the original equation has (y-1) the only option you can subtract 1 from to get between -1 and -2 is -1/2 which would give -1 1/2.