(6a^3+7a^2) -(5a^3+9a^2+a)=(6a 3 +7a 2 )−(5a 3 +9a 2 +a)=left parenthesis, 6, a, cubed, plus, 7, a, squared, right parenthesis, minus, left parenthesis, 5, a, cubed, plus, 9, a, squared, plus, a, right parenthesis, equals