5. 15y^2+4.5y-24y-7.2=0
15y^2-19.5y-7.2=0
Д=(-19.5)^2 - 4*15*(-7.2) = 812.25
x1=(19.5+28.5)/30 = 1.6
<span> x2=(19.5-28.5)/30 = -0.3
3. 0,6y-1.8-0.5y+0.5-1.5=0
0.1y-2.8=0
0.1y=2.8
y=28</span>
96 - х = 72
- х = 72 - 96
- х = - 24
х = 24
№4
y = x^2 + 5
x^2 = y - 5
x = y - 5 / x дробь
обратная
y = x - 5 / y дробь