Question

Решите уравнения: 1) (12y + 30)(1,4 - 0,7y) = 0

Answer 1

(12y+30)(1,4-0,7y)=0
16.8y-8.4y^2+42-21y=0
-8.4y^2-4.2y+42=0
2y^2+1-10=0
D=1+80=81
y=-1+-9/4
y1=2.5
y2=-2