Réponses

2014-05-05T20:38:19+02:00
A(x)=(3x-2)²-3(x+2)(4x-3)=9x²-12x+4-3(4x²-3x+8x-6)=9x²-12x+4-12x²+9x-24x+18=)
B(x)=(x+5)(x-5)+3(x+1)²=x²-25+3(x²+2x+1)=x²-25+3x²+6x+3=4x²+6x-22)
C(x)=16(x-1)²-(2x-5)²=[4(x-1)+(2x-5)][4(x-1)-(2x-5)]=(4x-4+2x-5)(4x-4-2x+5)=(6x-9)(2x+  1)
D(x)=(3x+7)[2(4x+5)+(2x-5)]=(3x+7)(8x+10+2x-5)=(3x+7)(10x+5)
2(x-V2)=V2-5x        2x-2V2=V2-5x       2x+5x=V2+2V2   7x=3V2     x=3V2/7
x/3-8-2x/7<-2        x/3-2x/7<-2+8     (7x-6x)/21<6       x/21<6    x<126