(3x+1)²-9(x-1)(x+1)=0

9x²+6x+1-9(x²-1)=0

9x²+6x+1-9x²+9=0

6x+9=0

6x=-9

x=-9/6

x=-1,5

1/9*x²=0.81

x²=0,81*9

x²=7,29

x₁=-2,7

x₂=2,7

a)(3х+1)^2-9(x²-1²)=0
9x²+6x+1-9x²-9=0
6x+10=0
x=-10/6

б)1/9* х^2=0,81

x^2=0.81*9

x^2=7.29

x(1)=2.7

x(2)=-2.7