8)
3a + (4-2a^2)/a = (3a^2 + 4-2a^2)/a = (a^2+4)/a
9)
x^2+7x-30=0
x^2+10x-3x-30=0
x(x+10)-3(x+10)=0
(x+10)(x-3)=0
x= -10 x=3
10)
x+2y=4 *2 2x+4y=8
2x+y=2 2x+y=2
3y=6
y=2
x=0
X^2-6x+9
25-x^2
36x^2-12x+1
36x^2-4
4+16a+16a^2
9b^2-1
49x^2-56x+16
162x^2+36x
(7+2a)=49a^2+28a+4b^2
Ax = -0,7
a = -0,7/x
при x = 6:
a = -0,7/6
a = -4,2