Question

Ajutati-ma va rog !!!

1. Sa se descompuna in factori:
a) 4(x+1)²-9x²=
b) 9(x-2)²-(2x-5)²=
c) 4x²(x-1)²-36x²=
d) 36x²-49(x-3)²=

Answer 1

a) [ 2( x +1) - 3x][ 2( x + 1) + 3x] = ( 2x + 2 - 3x)( 2x + 2 + 3x)
     = ( 2 - x)( 5x + 2)
b) [ 3( x - 2) - ( 2x - 5)][ 3( x - 2) + ( 2x - 5)] = ( 3x - 6 - 2x + 5)( 3x - 6 + 2x - 5)
     = ( x - 1)( 5x - 11)
c) [ 2x( x - 1) - 6x][ 2x( x - 1) + 6x] = ( 2x² - 2x - 6x)( 2x² - 2x + 6x)
     = ( 2x² - 8x)( 2x² + 4x) = 2x( x - 4) · 2x( x + 4) = 4x²( x - 4)( x + 4)
d) [ 6x - 7( x - 3)] [ 6x + 7( x - 3)] = ( 6x - 7x + 21)( 6x + 7x - 21)
       = ( 21 - x)( 13x - 21)