Find the zeroes of the function algebraically. Write the answer, if applicable, in fraction form. ƒ(x) = 2x2 - 3x - 20

2x^2 -3x - 20  =  0   

This factors as

(2x + 5) (x - 4)  = 0

Setting both factors to 0 and solving for x gives the zeroes x = 5/2  and x  = 4