Найдите корни уравнения (2,5*у -4)(6*у+1,8) = 0

Question

Найдите корни уравнения (2,5*у -4)(6*у+1,8) = 0

Answer 1

(2,5*у -4)(6*у+1,8) = 015y^2+4.5y-24y-7.2=0
15y^2-19.5y-7.2=0
D=380.25+432=812.25
y1=19.5+28.5/30=1.6
y2=19.5-28.5/30=-0.3

Answer 2

(2.5y-4)(6y+1.8)=0
15y^2-19.5y-7.2=0
D=(-19.5)^2-4*15(-7.2)=812.25
y1=(√815.25-(-19.5))/2*15=1.6
y2=(-√812.25-(-19.5)/2*15)=-0.3