x2(10-x)=21
10x-x2=21
-x2+10x-21=0
D=102-4*(-1)*(-21)=100-84=16
x1=-10+4/2*(-1)=-6/(-2)=-3
x2=-10-4/2*(-1)=-14/-2=-7
ա)
x*(x+1)=110
x2+x-110=0
D=1-4*1*(-110)=1+440=441
x1=(-1)+√441/2*1=(-1)+21/2=20/2=10
x2=-1-21/2=-11
x=10
x+1=10+1=11
գ)x(x+7)=44
x2+7x-44=0
D=72-4*1*(-44)=49+176=225
x1=-7+15/2=8/2=4
x2=-7-15/2=-22/2=-11
x=4
x+7=4+7=11
ա)x2(20-x)2=x2+400-40x+x2=218
x2+400-40x+x2-218=0
2x2-40x+182=0