1. х^2-2*2х+2^2 = х^2-4х+4
2. ??
3. (2у)^2-(7х)^2 = 4у^2 - 49х^2
4. (3х)^2+2*3х*12у+(12у)^2=9х^2+72ху+144у^2
5. -(11-15х)(11+15х)=-(11^2-(15х)^2)=-121+225х^2
6. 9^2+2*9*8х+(8х)^2=81+144х+64х^2
7. (11х^2)^2-2*(11х^2)*6+6^2=121х^4-132х^2+36
8. (2х^2)^2+2*(2х^2)*3+3^2=4х^4+12х^2+9
9. (5х)^2-3^2=(5х-3)*(5х+3)
10. (11х^2)^2-2*(11х^2)*6+6^2=121х^4-132х^2+36
11. (2х)^2-5^2=(2х-5)*(2х+5)