Question

the derivative function of y = ax^2 + bx + c is y = 4x + 2. the function has a zero at x = 1. find the values of a, b and c

Answer 1

a=2 b=2 c=1? I think.

Answer 2

first find the derivative of ax^2 + bx + c and compare with y' = 4x + 2 :
y'=2ax+b then we know that y' = 4x + 2
therefore
2a=4 so a=2 , then
b = 2

Also they say that y=0 at x=1 which means:
f(x)=y=ax^2 + bx + c
f(1)= a(1)^2 + b(1) + c
0= a + b + c
plug in the values of a=2 and b=2 in the function
0= 2 + 2 + c
c=-4
therefore the values are:
a=2
b=2
c=-4