<span>(1+5у)(5у-1)=10у-1
5y-1+25y^2-5y-10y+1=0
25y^2-10y=0
D=100
y1=10+10/50=0.4
y2=10-10/50=0
</span>
4(3-y)-2y=6;
12-6y=6;
12-6=6y;
6=6y;
y=1;
x=3-1=2
Ответ (2;1)
{3x<22, 2x>4
{x<22/3, x>2
{x<7 1/3 , x>2
(2; 7 1/3)
ответ: 5, 6
2x = 3x - 3
x = 3
2x - 7 = 8 - x
3x = 15
x = 5
x1*x2 = 3 * 5 = 15