Find the value of the expression (4x−12)+(12xy−10)(4x-12)+(12xy-10) for x=4 and y=6

(4x−12)+(12xy−10)(4x-12)+(12xy-10) = 4x-12 + 12.4.x.x.y - 12.12 .xy -10.4.x + 10.12 + 12xy - 10 
            = 4x - 10 +48(x^2)y - 144xy - 40x + 120 + 12xy -10
            = 48yx^2 + 4x -40x -144xy + 12xy -10+120-10
            = 48yx^2 - 36x - 132xy + 100
For x = 4 and y = 6
(4x−12)+(12xy−10)(4x-12)+(12xy-10) =  48yx^2 - 36x - 132xy + 100
                                                            = 48.6.(4^2) - 36.4 - 132.4.6 + 100
                                                            = 4608 - 144 - 3168 + 100
                                                            = 1396

8doors on the second floor

Two because two of one thing is two.