developper et reduire (x-4)(2x+1)-(5x-2)*6x (2z-5)(8-z)-(3z+1)(z-6) 2y(1+y)+(2y+3)(8-11y) (-7m+3)(m-3)-6(8m-3) 3/2(4t+14)+5/4(8-20t)

bonjour

1) 2 x² + x - 8 x - 4 - ( 30 x² - 12 x ) = 2 x² - 7 x - 4 + 30 x² + 12 x = 32 x² + 5 x - 4

2) 16 z - 2 z² - 40 + 5 z - ( 3 z² - 18 z + z - 6) = - 2 z² + 21 z - 40 - 3 z² + 18 z - z + 6
= - 5 z² + 38 z - 34 

3) 2 y + 2 y² + 16 y - 22 y² + 24 - 33 y = - 20 y² - 15 y + 24

4) - 7 m² + 21 m + 3 m - 9 - 48 m + 18 = - 7 m² - 24 m + 8

5) 12 t/2 + 42/2 + 40/4 - 100 t/4 =  6 t + 21 + 10 - 25 t = - 19 t + 31