ա) x2-9x+8x-72=-52
x2-9x+8x-72+52=0
D=b-4ac=(-1)2-4*1*(-20)=1+80=81>0
x1=-b+√81/21=1+9/2=5
x2=1-9/2=-8/2=-4
գ)x2+2x+x+2=4x2-20x-2x+10
x2+2x+x+2-4x2+22x+2x-10=0
-3x2+25x-8=0
D=b2-4ac=252-4*(-3)*(-8)=625-96=529>0
x1=b+√D/2a=-25+23/2*(-3)=-2/-6=1/3
x2=-25-23/2*(-3)=-48/-6=8
ա)D=b2-4ac=62-4*1*8=36-32=4
x1=-b+√D/2a=-6+2/2=-4/2=-2
x2=-6-2/2=-8/2=-4
ա)x1+x2=L
x2-3x-28=0