X - 4
x2+14x+40 = (x+4)(x+10) when factored
(x - 5)(x - 8)
(x + 5)(x + 8)
X3 + 13X2 + 40X factor out an X X(X2 + 13X + 40) factor the quadratic expression, what two factors of 40 add up to 13? X(X + 8)(X + 5) works the same if that is a negative in front of X3, just sign changes
(x2 plus 40) (x minus 1)
x - 4 APEX
(x + 10)(x + 4)
You didn't bother to list the binomials to choose from, but the two binomial factors of x2 + 6x - 40 are (x + 10) and (x - 4)
(x + 10)(x + 4)
x2+14x+40 = (x+4)(x+10) when factored
(x - 5)(x - 8)
(x + 5)(x + 8)
(x + 8)(x - 5)
x2+14x+40 = (x+4)(x+10) when factored
x2-7x-44 (x-11)(x+4)
X3 + 13X2 + 40X factor out an X X(X2 + 13X + 40) factor the quadratic expression, what two factors of 40 add up to 13? X(X + 8)(X + 5) works the same if that is a negative in front of X3, just sign changes
You should look for two numbers whose product is 40, and whose sum is 13. Experimenting a little (trying different pairs of factors for 40), you can quickly realize that this works for 8 and 5. Therefore, x2 + 13x + 40 = (x + 8) (x + 5)