Question

What are the zeros of the function f(x)=x^2+x-20?

Answer 1

-5 and 4

those are the correct answers

Answer 2

The zeroes of the given function are -5 and 4.

Explanation:

The given function is

`f(x)=x^2+x-20`

Equate the given function equal to 0, to find the zeroes of the given function.

`x^2+x-20=0`

Write the middle term as 5x-4x.

`x^2+5x-4x-20=0`

`(x^2+5x)+(-4x-20)=0`

Taking out common factors from each parenthesis.

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

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

Using zero product property, we get

`x-4=0\Rightarrow x=4`

`x+5=0\Rightarrow x=-5`

Therefore the zeroes of the given function are -5 and 4.