(x-3)(x+3)=(2x-3)²-18
x^2-9 = 4x^2-12x+9-18
x^2=4x^2-12x
-3x^2×(x-4)=0
x=0;x=4
1) 14:2=72)11-2=9
3)81:9=9
4)9*8=72
5)9*7=63
6)72+63=135