Bonsoir,
Développer et réduire.
A = (7x - 2)(7x + 2) - x(14 - 3)
→ identité remarquable :
A= (7x)² - 2² - x*11
A = 49x² - 4 - 11x
A = 49x² - 11x - 4
B = (4x + 1)(4x - 1)
→ identité remarquable :
B = (4x)² - 1²
B = 16x² - 1
C = 2x - 3(7 - x) - 2(1 - x)
C = 2x - (3*7 + 3*(-x)) - ( 2*1 + 2*(-x))
C = 2x - (21 - 3x) - (2 - 2x)
C = 2x - 21 + 3x - 2 + 2x
C = 7x - 23
D = (7x - 5)(2 - 3x) - 4(1 + x)
D = 7x*2 + 7x*(-3x) + (-5)*2 + (-5)*(-3x) - 4(1 + x)
D = 14x - 21x² - 10 + 15x - (4*1 + 4*x)
D = 14x - 21x² - 10 + 15x - 4 - 4x
D = -21x² + 25x - 14
E = 4x(3 - x) - 5(2 - 3x)
E = 4x*3 + 4x*(-x) - (5*2 + 5*(-3x))
E = 12x - 4x² - (10 - 15x)
E = 12x - 4x² - 10 + 15x
E = -4x² + 27x - 10
F = 2 - x(3 - x) + x² - 2x(x - 5)
F = 2 - (x*3 + x*(-x)) + x² - (2x*x + 2x*(-5))
F = 2 - (3x - x²) + x² - (2x² - 10x)
F = 2 - 3x + x² + x² - 2x² + 10x
F = 7x + 2
G = (4x - 3)(1 - x) + 2x(3 - x)
G = 4x*1 + 4x*(-x) + (-3)*1 + (-3)*(-x) + 2x(3 - x)
G = 4x - 4x² - 3 + 3x + 2x(3 - x)
G = -4x² + 7x - 3 + 2x*3 + 2x*(-x)
G = -4x² + 7x - 3 + 6x - 2x²
G = -6x² + 13x - 3
* = multiplication
Bonne soirée.
bonsoir
A:(7x-2)(7x+2)-x(14-3)
= 49 x² - 4 - 14 x + 3 x
= 49 x² - 11 x - 4
B:(4x+1)(4x-1) = 16 x² - 1
C:2x-3(7-x)-2(1-x) = 2 x - 21 + 3 x - 2 + 2 x = 7 x - 23
D:(7x-5)(2-3x)-4(1+x) = 14 x - 21 x² - 10 + 15 x - 4 - 4 x = - 21 x² + 25 x - 14
allez continue