1.(a-6)^2=a^2-12a^2+36
2. (5x+2y)^2=25x^2+20ху+4у^2
3. (10+7к)^2 = 100+140к^2+49к^2
4. (3с-1)(3с+1)=9с^2-1
5. (9+х)^2 =81+18х+х^2
1.(a-6)^2=a^2-12a^2+36
2. (5x+2y)^2=25x^2+20ху+4у^2
3. (10+7к)^2 = 100+140к^2+49к^2
4. (3с-1)(3с+1)=9с^2-1
5. (9+х)^2 =81+18х+х^2