Irene R. answered • 03/11/20
Senior Mechanical Engineer with 13+ years of Teaching Experience
I assume that you want to solve these two equations with two unknowns.
If we use elimination, we can multiply the first equation by -3 and the second equation by 2 to solve for x initially:
6 x + 2 y = -12 multiply by -3 and the equation becomes: -18 x - 6 y = 36
4 x + 3 y = 7 multiply by 2 and the equation becomes : 8 x + 6 y = 14
Now combine the equations:
-18 x - 6 y = 36
8 x + 6 y = 14
-10 x = 50
x = -5
Then substitute -5 for x in either of the original equations to find the value of y:
6 x + 2 y = -12
6 * (-5) + 2 y = -12
-30 + 2 y = -12
-30 + 2 y + 30 = -12 + 30
2 y = 18
y = 9
We can verify by substituting x = -5 and y = 9 in the second original equation:
4 x + 3 y = 7
4* (-5) + 3* 9 = -20 + 27 =7
