# How do you find zeros of y=-4x^3+100x?

Sep 20, 2016

$x = 0 , x = \pm 5$

#### Explanation:

The zeros of the function are the values of x that make y = 0.

solve: $- 4 {x}^{3} + 100 x = 0$

Factorising gives.

$- 4 x \left({x}^{2} - 25\right) = 0 \Rightarrow - 4 x \left(x - 5\right) \left(x + 5\right) = 0$

$\Rightarrow x = 0 \text{ and " x=+-5" are the zeros}$