Question

If x^3+ax^2-18x+b = (x+5)(x-4)(x+2) what is a and b

Answer 1

♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️

`(x + 5)(x - 4)(x + 2) =`

`(x + 5) ({x}^(2) - 2x - 8) =`

`{x}^(3) - 2 {x}^(2) - 8x + 5 {x}^(2) - 10x - 40 = \\`

`{x}^(3) + 3 {x}^(2) - 18x - 40`

_________________________________

Compare :

`{x}^(3) + 3 {x}^(2) - 18x - 40`

`{x}^(3) + a {x}^(2) - 18x + b`

Thus :

`a = 3`

and

`b = - 40`

♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️