3)
-x2 + 4x = - 3.
y - 2y = - 5.
-x(x-4) = - 3
-y = - 5 y=5
-x = - 3
x=3
x-4 = - 3
x= 1
1)
0,5x+x2=2
-y-2y= -1
X(0,5+x) = 2
-3y= - 1
X=2
0,5+x=2 x=1,5
3y=1 y= - 2
