If x/y = 5/z, then 25y^2 =	Choose the most appropriate option:
A) x²z²
B) 3x²
C) (1/9)x²z²
D) x²z
E) x²/9
This question is most easily solved by isolating y in the equation and substituting into the expression 25y²:   x/y = 5/z   x = 5y/z   5y = xz   y = xz/5.   If we substitute xz/5 into the expression for y, we get:   25(xz/5)² = 25(x²z²/25) = x²z².   The correct answer is choice (x²z²)
<result>A</result>
If x/y = 5/z, then 25y^2 =