A) x^2-5=2x^2-x+10x-5
x^2=2x^2-x+10x
x^2=2x^2+9x
x^2-2x^2-9x=0
-x^2-9x=0
-x(x+9)=0
-x=0 x+9=0
x=-9
б) 2x-(x^2+2x+1)=3x^2-6
2x-x^2-2x-1=3x^2-6
-x^2-1=3x^2-6
-x^2-3x^2=-6+1
-4x^2=-5
x^2=5/4
x= ±√5/2
в) 6a^2-(a^2+4a+4)=-4a+16
6a^2-a^2-4a-4=-4a+16
6a^2-a^2-4=16
5a^2-4=16
5a^2=16+4
5a^2=20
a^2=4
a= ±2
г) 5y^2-15y+2y-6=-26-13y
5y^2-13y-6=-26-13y
5y^2-6=-26
5y^2=-26+6
5y^2=-20
y^2=-4
∅