a)
3x=(2x-3)(2x+3)-4x²
3x=4x²-9-4x²
3x=-9/3=-3
X=-3
b)
(3x-4)²-(3x+2)²=-24
9x²-24x+16-(9x²+12x+4)=-24
9x²-24x+16-9x²-12x-4+24=0
-36x+36=0
36x=36
X=1
5.
(m+n)²/2 - (m-n)²/2=2mn // *2
(m+n)² –(m-n)^2=4mn
m^2+2mn+n²-(m²-2mn+n²)=4mn
m²+2mn+n²-m²+2mn-n²=4mn
4mn =4mn