Question

0.1x+0.2y=-1;0.5x-0.9y=6.4

Answer 1

.1x+.2y=-1
.5x-.9y=6.4

×-5 equation .1x+.2y=-1

-.5x-y=5
.5x-.9y=6.4

solve by elimination

-1.9y=11.4
÷-1.9 both sides
y=-6

solve for X

.1x+.2 (-6)=-1
.1x-1.2=-1
+1.2 both sides
.1x=.2
÷ 1 both sides
x=2

plug into 2nd equation to see if it's true

x=2
y=-6

0.5(2)-0.9(-6)=6.4
1+5.4=6.4
6.4=6.4 answers hold true