aide svp pour mon dm !?

A= (4x-3)² - (4x-3) (3-9x)
1. développer et réduire
A= 16x² -24x +9 -( 12x - 36x²- 9 + 27x)
A= 52 x² - 63 x +18
2. factoriser
A= (4x-3)² - (4x-3) (3-9x)
A = (4x-3) (4x-3 -3+9x)
A = (4x-3) ( 13 x - 6)
3. calculer A pour x=2
(4x-3) ( 13 x - 6)=
8-3 * (26-6)=
5*20=
A= 100 pour x=2
4. factoriser B=(7x-3)² - 9
B= (7x-3)² - 3²
B= (7x-3-3) ( 7x-3+3)
B= (7x-6) 7x

Answer Link

ch23 ch23 · Answer 2 · 2013-12-27T01:26:13+01:00

1) ( 4 x -3)² - (4x-3) (3-9x)
(4x)²-2*4x*3+3²) - (4x-3)*(4x-9x)*((-3)+3)*(-3-9x)
(16x²-24x+9) -   (4x-3)*(-5x)*((-3+3)*(-3-9x)
4x*(-5x)*(-9x)=180³
-3+3*-3= -3+(-9)=-12
(16x²-24x+9) - (180x³ -12)
16x²-24x+9-12- 180x³
16x²-24x-21-180x³

2)
A= (4x-3)² - (4x-3) (3-9x)
A = (4x-3) (4x-3 -3+9x)
A = (4x-3) ( 13 x - 6)

3) (4x2 -3)² - (4x2-3) (3-9x2)
  (8-3)² - (8-3) (3-18)
25 - 5 * (15)
25-(-75)=100
4)
A = (7x - 3)  - 9
=(7x - 3) x (7x - 3) - 3 x 3
=[(7x - 3) + 3] x [(7x - 3) - 3]
  [(7x - 3) + 3] = [7x - 3 + 3] = (7x)
  [(7x - 3) - 3] = [7x - 3 - 3]= (7x - 6)
A = 7x (7x - 6)