A) 3x -3y =3(x -y)
b) a² -9b² =(a -3b)(a +3b)
в) a² -4a +4 =(a -2)² =(a -2)(a -2)
г) a(b-c) +3(c-b) =a(b -c) -3(b -c) =(b -c)(a -3)
д) 3a+3 -na -n =3(a+1) -n(a +1) =(a +1)(3 -n)
8x(1+2x) -(4x+3)(4x -3) =2x
8x +16x² -(16x² -9) -2x =0
6x +16x² -16x² +9 =0
6x = -9
x = -9/6
x = -3/2
x = -1.5
x² = -3x +4
x² +3x =4
x² +3x -4 =0
D=9 +16 =25 =5²
x1 =(-3 -5)/2 = -4
x2 =(-3 +5)/2 =1