Sagot :
Bonsoir,
Exercice 107
1) A = (2x - 3)² - (4x + 7)(2x - 3)
A = (4x² - 12x + 9) - (8x² - 12x + 14x - 21)
A = 4x² - 12x + 9 - 8x² + 12x - 14x + 21
A = -4x² - 14x + 30
2) A = (2x - 3)² - (4x + 7)(2x - 3)
A = (2x - 3)(2x - 3) - (4x + 7)(2x - 3)
A = (2x - 3)[(2x - 3) - (4x + 7)]
A = (2x - 3)(2x - 3 - 4x - 7)
A = (2x - 3)(-2x - 10)
A = -2(2x - 3)(x + 5)
3) x = 0
A(0) = (2*0 - 3)² - (4*0 + 7)(2*0 - 3)
A(0) = (-3)² - 7*(-3)
A(0) = 9 + 21
A(0) = 30
x = -5
A(-5) = [2*(-5) - 3]² - [4*(-5) + 7] [2*(-5) - 3]
A(-5) = (-10 - 3)² - (-20 + 7)(-10 - 3)
A(-5) = (-13)² - (-13)(-13)
A(-5) = 169 - 169
A(-5) = 0
[tex]x=\dfrac{3}{2}\\\\A(\dfrac{3}{2}) = (2\times\dfrac{3}{2} - 3)^2 - (4\times\dfrac{3}{2} + 7)(2\times \dfrac{3}{2} - 3)\\\\A(\dfrac{3}{2}) = (3 - 3)^2 - (6 + 7)(3 - 3)\\\\A(\dfrac{3}{2}) =0^2-13\times 0\\\\A(\dfrac{3}{2})=0 [/tex]
Exercice 108
1) B = 4x(5x - 2) + 25x² - 4
B = 20x² - 8x + 25x² - 4
B = 45x² - 8x - 4
2) 25x² - 4 = (5x + 2)(5x - 2)
3) B = 4x(5x - 2) + 25x² - 4
B = 4x(5x - 2) + (25x² - 4)
B = 4x(5x - 2) + (5x + 2)(5x - 2)
B = (5x - 2)[4x + (5x + 2)]
B = (5x - 2)(4x + 5x + 2)
B = (5x - 2)(9x + 2)
Exercice 107
1) A = (2x - 3)² - (4x + 7)(2x - 3)
A = (4x² - 12x + 9) - (8x² - 12x + 14x - 21)
A = 4x² - 12x + 9 - 8x² + 12x - 14x + 21
A = -4x² - 14x + 30
2) A = (2x - 3)² - (4x + 7)(2x - 3)
A = (2x - 3)(2x - 3) - (4x + 7)(2x - 3)
A = (2x - 3)[(2x - 3) - (4x + 7)]
A = (2x - 3)(2x - 3 - 4x - 7)
A = (2x - 3)(-2x - 10)
A = -2(2x - 3)(x + 5)
3) x = 0
A(0) = (2*0 - 3)² - (4*0 + 7)(2*0 - 3)
A(0) = (-3)² - 7*(-3)
A(0) = 9 + 21
A(0) = 30
x = -5
A(-5) = [2*(-5) - 3]² - [4*(-5) + 7] [2*(-5) - 3]
A(-5) = (-10 - 3)² - (-20 + 7)(-10 - 3)
A(-5) = (-13)² - (-13)(-13)
A(-5) = 169 - 169
A(-5) = 0
[tex]x=\dfrac{3}{2}\\\\A(\dfrac{3}{2}) = (2\times\dfrac{3}{2} - 3)^2 - (4\times\dfrac{3}{2} + 7)(2\times \dfrac{3}{2} - 3)\\\\A(\dfrac{3}{2}) = (3 - 3)^2 - (6 + 7)(3 - 3)\\\\A(\dfrac{3}{2}) =0^2-13\times 0\\\\A(\dfrac{3}{2})=0 [/tex]
Exercice 108
1) B = 4x(5x - 2) + 25x² - 4
B = 20x² - 8x + 25x² - 4
B = 45x² - 8x - 4
2) 25x² - 4 = (5x + 2)(5x - 2)
3) B = 4x(5x - 2) + 25x² - 4
B = 4x(5x - 2) + (25x² - 4)
B = 4x(5x - 2) + (5x + 2)(5x - 2)
B = (5x - 2)[4x + (5x + 2)]
B = (5x - 2)(4x + 5x + 2)
B = (5x - 2)(9x + 2)