${x}_{1}+3{x}_{2}-{x}_{3}+{x}_{4}+2{x}_{5}=2,$

$2{x}_{1}-{x}_{2}+{x}_{3}-{x}_{4}+{x}_{5}=-2,$

$4{x}_{1}+2{x}_{2}+2{x}_{3}-{x}_{4}-{x}_{5}=0.$

I thought that I could multiply 1 by equation 2, and then add that to equation 1, which would cancel both the ${x}_{3}$ and the ${x}_{4}$ factors for that line. Is that permissible?