Answer
$2x-2$
Work Step by Step
$(x+4)(x-5)$= mutiply each term of the second binomial with each term of the first
... (use the FOIL method)
$=x^{2}-5x+4x-20\qquad$... combine like terms
$=x^{2}-x-20\qquad (*)$
$(x+3)(x-6)$= use the same method as above.
$=x^{2}-6x+3x-18$
$=x^{2}-3x-18\qquad (**)$
$(*)-(**)=(x^{2}-x-20)-(x^{2}-3x-18)$
... distribute - take down the parentheses
$=x^{2}-x-20-x^{2}+3x+18$
... combine like terms
$=(x^{2}-x^{2})+(-x+3x)+(-20+18)$
$=0+2x-2$
= $2x-2$
