Решить уравнение1)х^2-7х=02)4х^2-169=03)6х^2+х-2=04)3х^2+6х=8х^2-15х

1)х²-7х=0 x(x-7)=0 x=0   x-7=0          x=7 2)4х²-169=0 4x²=169 x²=[latex] \frac{169}{4} [/latex]>0 [latex] x_{1} = \sqrt{ \frac{169}{4} } = \frac{13}{2} =6 \frac{1}{2} =6,5[/latex] [latex] x_{2} =- \sqrt{ \frac{169}{4} } = -\frac{13}{2} =-6 \frac{1}{2} =-6,5[/latex] 3)6х²+х-2=0 D=1²-4*6*(-2)=49=7²>0 [latex] x_{1} = \frac{1+ \sqrt{7 ^{2} } }{2*6} = \frac{8}{12} = \frac{2}{3} [/latex] [latex] x_{2} = \frac{1- \sqrt{7 ^{2} } }{2*6} = \frac{-6}{12} = -\frac{1}{2} =-0,5[/latex] 4)3х²+6х=8х²-15х -5x²+21x=0 x(-5x+21)=0 x=0  -5x+21=0         -5x=-21          x=4,2