[tex]( - 7 {a}^{2} {b}^{4} ) ^{2} = ( - 7) ^{2} {( {a}^{2} })^{2} ( { {b}^{4} })^{2} \\ = 49 {a}^{2 \times 2} {b}^{4 \times 2} \\ = 49 {a}^{4} {b}^{8} [/tex]
