Question

упростите выражение
(a+2)^2-4a-a^2
12x+3(2-x)^2
3t(5t+4)+(6-t)^2
(2a+3)^2-6a(a+2)

Answer 1

1)(a+2)^2-4a-a^2=a^2+4a+4−4a−a^2=4;
2)12x+3(2-x)^2=12x+3(4−4x+x^2)=12x+12−12x+3x^2=3x^2+12;
3)3t(5t+4)+(6-t)^2=15t^2+12t+36−12t+t^2=16t^2+36;
4)(2a+3)^2-6a(a+2)=4a^2+12a+9−6a^2−12a=−2a^2+9.