Developper puis reduire chaque expression 
a) 6(-4x-5)+7   b) -5(6-4y)-5y
c) 5(-2a+7)+3a  d) 3b(5-6b)-9b

Reduire les expressions
a= 4x²+5x²     B=2x²-2x-5x²+4x
C=3t-2-6t-3     D=2xX3xX1sur2


Sagot :

a) 6(-4x-5)+7
= -24x-30+7
= -24x-23

b) -5(6-4y)-5y
= -30+20y-5y
= 15y-30

c) 5(-2a+7)+3a  
= -10a+35+3a
= -7a+35

d) 3b(5-6b)-9b
= 15b-18b²-9b
= -18b²+6b


A = 4x²+5x²
A = 9x²

B = 2x²-2x-5x²+4x
B = -3x²+2x

C = 3t-2-6t-3    
C = -3t-5

D = 2x*3x*(1/2)
D = 6x²/2
D = 3x²