3x+5y=78 2x-y=0 the point of intersection of the lines has an x-coordinate of what

In order to find where these two lines intersect you must solve them simultaneously x 

3x +5y = 78 (1)

2x - y = 0 (2)

by multiplying eq (2) by 2 and adding it to eq (1)
    5(2x - y = 0) (3)
    10x - 5y = 0 (3)

eq(3) + eq (1) : 10x + 3x +5y - 5y = 78 + 0
                    ⇒  13x = 78
                    ⇒      x = 6

Uneed to add them up 27+18+23=68