Question

$(3a - a^{2})^{2} - a^{2} (a - 2)(a+2) + 2a(7 + 3a^{2} )$

Answer 1

$(3a - a^2)^2 - a^2 (a - 2)(a+2) + 2a(7 + 3a^2 )=\\9a^2-6a^3+a^4-a^4+4a^2+14a+6a^3=\\13a^2 + 14a$