Question

(10х-5)(15х-10)=30х^2-6х-39

Answer 1

$(10x-5)(15x-10)=30x^2-6x-39$
$150x^2+100x-75+50-30x^2+6x+39=0$
$120x^2+106x+14=0$
$60x^2+53x+7=0$
$D=2809-1680=1129$
$x_1= frac{-53+ sqrt{1129} }{120}$
$x_2= frac{-53- sqrt{1129} }{120}$

Answer 2

не учили квадратный корень