What is the axis of symmetry for f(x)=5(x+7)(x-5) a x=1 b x=-1 c x=6 d x=-6 let f (x) =x2-3x-4 what is the average rate of charge from x=7 to =10 a 24 b 14 c 66 d 42 on these been trying

What is the axis of symmetry for f(x)=5(x+7)(x-5)?  Multiply out this polynomial to obtain the equation of a parabola in the form y = ax^2 + bx + c.

f(x) = 5(x^2 - 5x + 7x -35)

Holding the coefficient 5, we have 1x^2 - 2x - 35.  Here a = 1 and b = -2, and
thus x = -b / (2a) provides the x-coord. of the axis of symm.  It is:

x = -(-2) / (2*1) = 1.

The axis of symmetry is the vertical line x = 1.

Hello!
your answer should be c