Question

How to find the zeros of f(x)=5(2x-5)(5x+4)

Answer 1

If xy=0 we assume x and y equal 0

so

the zeros are wehre f(x)=0
0=5(2x-5)(5x+4)
set each to zero
5 is not equal 0 so we don't do that

0=2x-5
5=2x
5/2=x

0=5x+4
-4=5x
-4/5=x

zeroes at x=5/2 and -4/5

Answer 2

5(2x-5)(5x+4) = 0

2x-5 = 0
2x = 5
x = 5/2 (Answer)

5x+4 = 0
5x = -4
x = -4/5 (Answer)