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Bonjour
Exercice 147
1. A = 5x(x+3)-7(2-5x)
A = 5x^2 + 15x - 14 + 35x
A = 5x^2 + 50x - 14
2. B = (4x-1)^2
B = (4x-1)(4x-1)
B = 16x^2 - 4x - 4x + 1
B = 16x^2 - 8x +1
3. C = (3x+5)^2 -(4-3x)(4+3x)
C = (3x+5)(3x+5) -(4^2-(3x)^2)
C = 9x^2 + 15x + 15x + 25 - (16-9x^2)
C = 9x^2 + 30x + 25 - 16 + 9x^2
C = 18x^2 + 30x + 9
Exercice 148
1. A = 100 - 9x^2
A = 10^2 - (3x)^2
A = (10-3x)(10+3x)
2. B = (2x-7)^2-(3x+4)^2
B = (2x-7-(3x+4))(2x-7+(3x+4)
B = (2x-7-3x-4)(2x-7+3x+4)
B = (-x-11)(5x-3)
3. C = (x+1)(2-x)+(x+1)^2
C = (x+1)(2-x+x+1)
C = 3(x+1)