Answer:
The zeroes of the given function are -5 and 4.
Step-by-step 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.