This is super hard. Need answer asap!

If y = 2x2 – 4x, what is the value of y when x equals 5?

3 answers

A. 10
B. 30
C.80
D.480
y = 2x^2 – 4x I suspect you mean

y = 2 * 25 - 20 = 50 - 20 = 30

Not super hard, try harder.
Hard? Not so. If

y = 2x^2-4x

then what is y when x=5? Just replace all the x's with 5's and you have

y = 2*5^2 - 4*5 = 30