Question

Third-degree, with zeros of −5, −4, and 1, and a y-intercept of −15

Answer 1

y = 3/4( x+5)( x+4) ( x-1)

Explanation:

The formula for the polynomial is

y = c( x- a1)( x- a2) ( x-a3) where c is a constant and a1,a2,a3 are the zeros

We have zeros -5,-4 and 1

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

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

We have a y intercept of -15

That means x=0 and y = -15

-15 = c ( 0+5)( 0+4) ( 0-1)

-15 = c( 5) ( 4) (-1)

-15 = c( -20)

Divide each side by -20

-15/-20 = c

3/4 =c

The equation is

y = 3/4( x+5)( x+4) ( x-1)