c urgent j'arrive pas a faire ses equations a) 3(2x+7)-4=7-5(4-3x) b) 2x(3x-4)+5=3x(2x-5)-4

bonsoir

a= 6 x + 21 - 4 = 7 - 20 + 15 x
a = 6 x - 15 x = 7 - 20 - 21 +4
a = - 9 x = - 30
x = 30/9 = 10 /3

b = 6 x² - 8 x + 5 = 6 x² - 15 x -4
  6 x² - 6 x² - 8x + 15 x = - 4 - 5
 7 x = - 9
x = - 9/7

a) 3(2x+7)-4=7-5(4-3x)
6x+21-4 = 7-20+15x
6x -15x = -13-17
-9x = -30
x = -30/-9
x = 10/3

 b) 2x(3x-4)+5=3x(2x-5)-4
6x²-8x +5 = 6x² -15x-4
6x²-8x -6x²+15x = -4-5
7x = -9
x = -9/7