if y' = 2x-4, which of the following is an equation for this curve if it passes through point (2,2)?

Question

anonymous · Answer

a) y = 2x -2
b) y = x^2 -2
c) y  = x^2-4x
d) y = x^2-4x+6
e) y = 2x^2-4x+2

anonymous · Answer

Have you done integration in your class yet?

anonymous · Answer

nope, we only learned power rule

anonymous · Answer

Well, makes things more difficult, but okay. So, would you know how to differentiate all your options, a through e?

anonymous · Answer

yes.
a = 2
b = 2x
c = 2x - 4
d = 2x - 4
e = 4x^3-4

anonymous · Answer

Well, the last one is 4x-4, but Im sure you knew that :P So clearly only c and d could work. In order to see which one, you would need to plug in x = 2 and see if you get y = 2
c: (2)^2 - 4(2) = ?
d: (2)^2 - 4(2) + 6 = ?

So which one of those gives you a y value of 2? Because the coordinate point basically says that when you plug in 2, you get an answer of 2

anonymous · Answer

oooh so the answer is d, thanks!!!

anonymous · Answer

Yep, np :)