7c(4c+2)^2=28c^2+14c-7+c^2
7с( 16с^2+16c+3) = 28c^2+14c-7+c^2
112c^3+112c^2+28c= 28c^2+14c-7+c^2
112c^3+112c^2+28c - 28c^2-14c-7+c^2 = 112c^3+85c^2+14c-7
7c(4c+2)^2=28c^2+14c-7+c^2
7с( 16с^2+16c+3) = 28c^2+14c-7+c^2
112c^3+112c^2+28c= 28c^2+14c-7+c^2
112c^3+112c^2+28c - 28c^2-14c-7+c^2 = 112c^3+85c^2+14c-7