А)(11x-1)+(1-7x)=11х-1+1-7х=4х
при x=4;
4*4=16
б)(6а+3)-(2а-1)=6а+3-2а+1=4а+4
при а=-1;
4*(-1)+4=-4+4=0
в)3в-(12-в)=3в-12+в=4в-12
при в=3;
4*3-12=0
г)(2-в)-(3+6в)=2-в-3+6в=5в-1
при в=-2
5*(-2)-1=-11
→ → → → → → → → → → → → → → →
AB+CD-MN+DC+BN-KM = AB + BN +NM +MK +<u>CD +DC</u> = AK + 0 = AK
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{Y=2+x
{X^2+x•(2+x)=12
x^2+2x+x^2=12;
2x^2+2x-12=0; |:2
X^2+x-6=0;
D=1+24=25;
X1=(-1+5)/2=2;
X2=(-1-5)/2=-3;
Y1=2+2=4;
Y2=2-3=-1.