You may have factored out an x on the left side of the equation and then thought you could set $\displaystyle{21}{x}+{1}\usepackage{cmbright}\Huge\$ equal to 2. However, you need to subtract 2 from both sides of the equation to get 0 on one side, then factor and solve. The correct answer is: $\displaystyle{x}=\frac{{-{1}}}{{3}}\usepackage{cmbright}\Huge\$ or $\displaystyle{x}=\frac{{2}}{{7}}\usepackage{cmbright}\Huge\$