if f(x)= (x-4)(x=3) determine the x intercept of the funtion if

y= -2f(x)...
i just don't know if the -2 affects the answer because that only affects the y co ordinates. in the book it says 4,-3 but i don't know why.
if this is true if the they were asking me to find the y interpct of the function what do i do. THANKS!!!!

You have a typo, but looking at their answers of 4, and -3 , I know it must have been

f(x) = (x-4)(x+3)

so we want
y = -2(x-4)(x+3)

for the x-intercepts, y = 0
then
-2(x-4)(x+3) = 0
x-4 =0 or x+3 = 0
x = 4 or x = -3 , as stated.

for y-intercept let x = 0, real easy ....
y = 2(0-4)(0+3) = -24