Find the x-coordinates of all points on the graph of y = x^3 - 4x^2 + 5x at which the tangent line is parallel to 2y - 10x - 7 = 0

Answer 1

the slope of the given line is 5

so find dy/dx for the cubic
and set that result equal to 5

you will get a quadratic which factors nicely.

let me know what values of x you got.

Answer 2

I got x=10/3 and x=6

Answer 3

3x^2 - 8x + 5 = 5
x(3x-8) = 0
x = 0 or x = 8/3

I don't understand how you got your answers.