Incorrect. In order to simplify an expression, first identify like terms, reorder the polynomial, and then combine like terms by adding their coefficients. The terms $\displaystyle{10}{a}{b}\usepackage{cmbright}\Huge\$ , $\displaystyle-{5}{b}{a}\usepackage{cmbright}\Huge\$ , and $\displaystyle{4}{a}{b}\usepackage{cmbright}\Huge\$ are like terms, and none of the other terms can be combined with them.