Sagot :
=5x+5-14x-21x
= -30x +5
= 8-10x-x+7
= -11x+15
= 3-7x-20x+35
= -27x + 38
=21-14x-8x+4
= -22x +25
= 7x-10+45x+63x-7
=115x -17
= -30x +5
= 8-10x-x+7
= -11x+15
= 3-7x-20x+35
= -27x + 38
=21-14x-8x+4
= -22x +25
= 7x-10+45x+63x-7
=115x -17
Réponse :
Bonsoir,
Rappel:
x*x=[tex]x^{2}[/tex]
x+x= 2x
(+ +)= +
(- -)= +
(- +)= -
(+ -)= -
x(1) ⇔ x*1
->5(x-1)-7x(2+3x)= 5*x + 5*(-1) - 7x*2 - 7x*3x
= 5x + (-5) - 14x - 21[tex]x^{2}[/tex]
= - 21[tex]x^{2}[/tex] - 9x - 5
->2x(4-5x)-(x-7)= 2x*4 + 2x*(-5x) - x - (-7)
= 8x + (-10[tex]x^{2}[/tex]) - x + 7
= 8x - 10[tex]x^{2}[/tex] - x + 7
= - 10[tex]x^{2}[/tex] + 7x + 7
->(3-8x)-5(4x-7)= 3 - 8x - 5*4x - 5*(-7)
= 3 - 8x -20x - (-35)
= 3 - 8x -20x + 35
= - 28x+ 38
->7(3-2x)-4x(2x-1)= 7*3 + 7*(-2x) - 4x*2x - 4x*(-1)
= 21 - 14x - 8[tex]x^{2}[/tex] - (-4x)
=21 - 14x - 8[tex]x^{2}[/tex] + 4x
= - 8[tex]x^{2}[/tex] + 10x + 21
->7x-5(2-9x)+7(9x-1)= 7x - 5*2 - 5*(-9x) + 7*9x +7*(-1)
= 7x - 10 - (-45x) + 63x + (-7)
= 7x - 10 + 45x + 63x - 7
= 115x - 17