ex 107
1) (2x-3)^2-(4x+7)(2x-3)
(4x^2-9)-(4x*2x)+(4x*(-3))+(7*2x)+(7*(-3))
(4x^2-8)-(8x^2)+(-12x)+(14x)+(-21)
4x^2-8-8x^2-12x+14x-21
-4x^2+2x-29
2) (2x-3) [(2x+3)-(4x+7)]
(2x-3)(2x+3-4x-7)
(2x-3)(-2x-4)
3) x=0
(2*0-3)^2-(4*0+7)(2*0-3)
(0-3)^2-(0+7)(0-3)
(-3)^2-(+7)(-3)
9-(-21)
9+21=30
x=-5
(2*(-5)-3)^2-(4*(-5)+7)(2*(-5)-3)
(-10-3)^2-(-20+7)(-10-3)
(-13)^2-(-13)(-13)
169-(+169)
169-169=0
x=3/2
(2*3/2-3)^2-(4*3/2+7)(2*3/2-3)
(6/2-6/2)^2-(12/2+7)(6/2-3)
(0)^2-(12/2+14/2)(6/2-6/2)
-26/2*0=0
ex108
4x(5x-2)+25^2-4
1) (4x*5x)+(4x*(-2))+25x^2-4
20x^2+(-8x)+25x^2-4
20x^2-8x+25x^2-4
45x^2+17x-4
2) (5x-2)[(5x+2)+4]
3) (5x-2)(5x+6)