you can try this $$ \begin{array}{lllllll} x & = & \exp_4 & + & \exp_4 & + & \exp_4 \\ & = & \exp_4 & + & \exp_4 & + & \exp_4 \\ & = & \exp_4 & + & \exp_4 & + & \exp_4 \end{array} $$ I hope it will solve your problem. renu