3x + 4y = 12

x + 2y = 10

x=-8 and y=9

Step-by-step explanation:

rewrite the equations to x+2y=10,3x+4y=12

sub 2y from both sides x+2y-2y=10-2y

substitue x=10-2y in 3x + 4y=12

3 (-2y+10) + 4y=12

distribute

add-30 to both sides

divide both sides by - 2

y=9

sustitute 9 for y in - 2y+10=x

x=-8