Question

-5х(х-2) + 5(х+1) = -1

Answer 1

$-5x(x-2)+5(x+1) = -1, \ -5x^2+10x+5x+5+1=0, \ -5x^2+15x+6=0, \ 5x^2-15x-6=0, \ D=(-15)^2-4cdot5cdot(-6)=225+120=345, \ x_{1,2}=frac{15pmsqrt{345}}{2cdot5}=frac{15pmsqrt{345}}{10}$