7x + 2y = 19
-x + 2y = 21
7x + 2y = 19
Subtract 2y from both sides
7x = 19 - 2y
Divide both sides by 7
x = (-2/7)y - (19/7)
x + 2y = 21
Substitute x for (-2/7)y - (19/7)
(-2/7)y - (19/7) + 2y = 21
Combine like terms
(12/7)y - (19/7) = 21
Add (19/7) to both sides
(12/7)y = (166/7)
Multiply both sides by (12/7)
y = (83/6)
x + 2y = 21
Substitute y for (83/6)
x + 2(83/6) = 21
Multiply 2 by (83/6)
x + (83/3) = 21
Subtract (83/3) from both sides
x = (-20/3)
x = (-20/3)
y = (83/6)
