## Elementary Linear Algebra 7th Edition

To transform this system to Row-Echelon form we will follows the steps bellow. Step 1: Subtract from the second equation the first one multiplied by $5$ term by term to eliminate $x$: $$5x-5x-15y-5\times(-3y) + 10z - 5\times 2 z = 18-5\times 18$$ which becomes $$0=-72.$$ What we got here in impossible which means that this system is contradictory and has no solutions.