:8х-6у-11х-4у 2(5х--8х) (х+4)(х+8) (5с-7)(3с+1)

-3x-2y
10x-2-2+8x=18x-4 x=4/18
x²+8x+4x+32=x²+12x+32 D=144-128=16 x1=-12+4/2=-8/2=-4 x2=-12-4/2=-16/2=-8
15c²+5c-21c-7=15c²-16c-7 D=256+420=676 x1=-15+26/30=11/30 x2=-15-26/30=-31/30