Question

Va rog frumos exercitiul 17 d) e) si f)

Answer 1

                                                      4                4
(2xy²- 7)(2xy²+7)- (2xy²- 1)²= 4x²y -49    -(4x²y- 4xy²+1)=
=4xy²-50

(5x-7)(2.(x+2)+ 3(x+1)) - ((4x-3)( 3.(x+3) +x- 6)=(5x- 7)(5x+7)-
-(4x-3)( 3x+9 +x- 6)= 25x² -49-(4x-3)(4x+3)=25x²-16x²- 49 +9=
=9x²-40


(x+1)(5(x+1)-2(x+4)) - (3x+2)(7 (x+2) - 4(x+3))= (x+1)(3x- 3)-
-(3x+2)(7x+14 - 4x - 12)=3(x+1)(x-1) - (3x+2)(3x+2)=3x²- 3 -
-(3x²+12x+4)=3x²-3x²- 12x -1=-12x -1