c est pour demain svp

a)
 -7/12 + 5/2 + 9/4=-7/12 + (5x6)/(2x6) +(9x3)/(4x3)=[-7 +(5x6)+(9x3)]/12=(-7+30+27)/12=50/12=6
b)
 -12/25 x 45/-16 x(-2)= 3/5  x  9 /4 x2=27/20 x2=54/20= 27/10
c)
(2x-3)² +4x(3x+2)=[(2x-3)(2x-3)]+12x²+8x= 4x²-6x-6x+9+12x²+8x= 16x²-4x+9
d)
(4x-1)(-x+3) -(5x+2)(-3x-2)= (-4x²+12x+x-3)-[(-15x²-10x-6x-4)]= - 4x²+12x+x-
3+15x²+10x+6x+4=11x²+29x+7