1)9x^2-4=0
9x^2=4
x^2=4|9
x= 2|3
x=-2|3
2)3x^2+2x=0
x(3x+2)=0
x=0
x=-2|3
3)2=7x^2=2
0=7x^2
7x^2=0
x^2=0
x=0
4)(2X-9)(X+1)=(X-3)(X+3)
X^2+2X-9X=X^2
2X^2-7X=X^2|
X^2-7X=0
X(X-7)=0
X=0
X=7
5)
3-(4X+1)(3-X)=X^2
-11X+4X^2-X^2=0
-11X+3X^2=0
-X(11-3X)=0
-X=0
11-3X=0
X=0
X=11|3