color(white)(+)-4x+2y=-12+−4x+2y=−12
color(white)(+)+
color(white)(+)color(white)(-)3x+2y=9+−3x+2y=9
We need to eliminate one of the variables. The yys are already equal, so we will subtract the two equations and remove 2y2y:
color(white)(+)-4x+cancel(2y)=-12
color(black)(-)
color(white)(+)color(white)(-)3x+cancel(2y)=color(white)(-)9
...............................................................
-7x=-21
Now we just solve for x
-7x=-21
Divide by 7 on both sides
x=(-21)/-7 or x=3
Now we have x; we need to find the value of y. To do that, we pick an equation and solve for y, substituting x for 3.
3x+2y=9
3(3)+y=9
9+y=9
9+y color(purple)(-9)=9color(purple)(-9)
y=0
Just to double check our work, let's solve the second equation using both x and y as 3 and 0, respectively.
-4x+2y=-12
-4(3)+2(0) should equal -12
-12+0=-12
We were right! Congratulations. Nice work.
Hope this is helpful
