Répondre :
a=2x-(4x+7)+5x(3-2x)
=2x-4x-7+15x-10x²
=10x²-13x-7
b=(x+5)²+(3x-1)(-4x+3)
=x²+10x+25-12x²+9x+4x-3
=-11x²+23x+22
c=(4x-2)²+(7+2x)(7-2x)
=16x²-16x+4+49-14x+14x-4x²
=12x²-16x+53
d=5x-(2x-1)(x+4).
=5x-2x²-8x+x+4
=-2x²-2x+4
=2x-4x-7+15x-10x²
=10x²-13x-7
b=(x+5)²+(3x-1)(-4x+3)
=x²+10x+25-12x²+9x+4x-3
=-11x²+23x+22
c=(4x-2)²+(7+2x)(7-2x)
=16x²-16x+4+49-14x+14x-4x²
=12x²-16x+53
d=5x-(2x-1)(x+4).
=5x-2x²-8x+x+4
=-2x²-2x+4