Answer:
x = 5, y = 2
Explanation:
I'll use substitution on this one, which makes me choose one of the equation and solve for x. (5x + 3y = 31 was chosen)
5x + 3y = 31
Subtracct 3y from both sides
5x = -3y + 31
Divide both sides by 5
x = 1/5 (-3y + 31)
Multiply 1/5 by -3y + 31
x = -3/5y + 31/5
Substitute -3/5y + 31/5 for x in the other equation (2x + y = 12)
2 (-3/5y + 31/5) + y = 12
Multiply -3/5y + 31/5 by 2.
-6/5y + 62/5 + y = 12
Add -6/5y to y
-1/5y + 62/5 = 12
Subtract 62/5 from both sides
-1/5y = -2/5
Multiply both sides by -5
y = 2
Now head back to the previous equation, except substitute y for 2.
x = -3/5 * 2 + 31/5
Multiply -3/5 by 2.
x = (-6 + 31)/5
Add -6 and 31
x = 25/5
Divide 25 by 5.
x = 5
Formulate 5 and 2 for x and y in the equation.
5(5) + 3(2) = 31
2(5) + 2 = 12
25 + 6 = 31; true
10 + 2 = 12; true
x is 5 and y is 2.