Write the system of equations as an augmented matrix. Then solve for x and y.

Question

5x-4y=12
-5x+3y=9

Answer 1

+5 -4 12 divide by 5 to get 1
-5 +3 +9

+1 -4/5 12/5 multiply by 5 and add
-5 +3.0 +9

+1 -4/5 12/5
+0 -1.0 21 multiply by -1

+1 -4/5 12/5
+0 +1.0 -21 so y = -21

now multiply second eqn by 4/5 and add to first
+1 -4/5 12/5
+0 +4/5 -84/5

+1 +0 -72/5
+0 +1 -21

x = -72/5, y = -21