Solve the equation using the Linear Equation Combination: x + y = 20; 10x + 12y =224?

x+y=20------------------eq:1
10x+12y=224--------------------eq:2

From eq:1 (x=20-y) put this in eq:2

10(20-y)+12y=224
200-10y+12y=224
2y=224-220
2y=4
y=4/2
y=2
And x=18