Решите уравнение: 1) 5x+x-4=0 2) 20x²+x-1=0 3) 8x²+10x+3=0 4)-6x²+7-2=0

1) 5х²+х-4=0     D=1²-4·5·(-4)=81 [latex] x_{1,2} [/latex]=[latex] \frac{-1+-9}{10} [/latex] [latex] x_{1} [/latex]=[latex] \frac{-1+9}{10} [/latex]=[latex] \frac{8}{10} [/latex]=0,8 [latex] x_{2} [/latex]=[latex] \frac{-1-9}{10} [/latex]=-[latex] \frac{10}{10} [/latex]=-1     2) [latex] 20x^{2} [/latex]+х-1=0   D=1²-4·20-1=81   [latex] x_{1, 2} [/latex]=[latex] \ \frac{-1+-9}{40} [/latex]   [latex] x_{1} [/latex]=[latex] \frac{-1+9}{40} [/latex]=[latex] \frac{8}{40} [/latex]=[latex] \frac{1}{5} [/latex]   [latex] x_{2} [/latex]=[latex] \frac{-1-9}{40} [/latex]=[latex] \frac{-10}{40} [/latex]=-[latex] \frac{1}{4} [/latex]   3) [latex] 8x^{2} [/latex]+10х+3=0  D=10²-4·8·3=4 [latex] x_{1,2} [/latex]=[latex] \frac{-10+-2}{16} [/latex] [latex] x_{1} [/latex]=[latex] \frac{-10+2}{16} [/latex]=-[latex] \frac{8}{16} [/latex]=-0,5 [latex] x_{2} [/latex]=[latex] \frac{-10-2}{16} [/latex]=-[latex] \frac{12}{16} [/latex]=-[latex] \frac{3}{4} [/latex]=-0,75 4)-6х²+7х-2=0 | ÷(-1) 6х²-7х+2=0 D=(-7)²-4·6·2=49-48=1 [latex] x_{1,2} [/latex]=[latex] \frac{7+-1}{12} [/latex] [latex] x_{1} [/latex]=[latex] \frac{7-1}{12} [/latex]=[latex] \frac{6}{12} [/latex]=0,5 [latex] x_{2} [/latex]=[latex] \frac{7+1}{12} [/latex]=[latex] \frac{8}{12} [/latex]=[latex] \frac{2}{3} [/latex]