For this case we have the following expression:
[tex](ab ^ 2 + 4a ^ 2 + 6a ^ 2b ^ 2) - (- ab ^ 2 + 2a ^ 2b ^ 2 + 4a ^ 2) =[/tex]
We must simplify taking into account that:
[tex]- * - = +\\- * + = -[/tex]
So, we have:
[tex]ab ^ 2 + 4a ^ 2 + 6a ^ 2b ^ 2 + ab ^ 2-2a ^ 2b ^ 2-4a ^ 2 =[/tex]
We add similar terms:
[tex]ab ^ 2 + ab ^ 2 + 4a ^ 2-4a ^ 2 + 6a ^ 2b ^ 2-2a ^ 2b ^ 2 =\\2ab ^ 2 + 4a ^ 2b ^ 2[/tex]
Answer:
[tex]2ab ^ 2 + 4a ^ 2b ^ 2[/tex]