Question

Write a cubic function whose graph goes through the points: (-5, 0) (1, 0) (2, -2) (4, 0)​

Answer 1

Explanation:

From points (-5,0),(1,0),(4,0) we know it has the form

y=(x+5)(x-1)(x-4)

y=(x^2+4x-5)(x-4)

y=x^3-4x^2+4x^2-16x-5x+20

y=x^3-21x+20

Then it must pass through the point (2,-2) so

-2=[2^3-21(2)+20]b

-2=[8-42+20]b

-2=[-14]b

b=1/7 so the equation is

y=(x^3-21x+20)/7