Given: x = 9 y − 3 x − y = − 5 Find the x-coordinate of the point of intersection of the two lines.

Answer 1

x = 9y - 3

x-y = -5

9y -3 - y = -5

8y - 3 = -5

8y = -5 +3 = -2

y = -2/8 = -1/4

x - -1/4 = -5

x + 1/4 = -5

4x + 1 = -20

4x = -21

x = -21/4

CHECK

9y - 3 = 9(-1/4) - 3 = -9/4 - 3 = -9/4 - 12/4 = -21/4 = x <--- first equation checks out

x-y = -21/4 - -1/4 = -20/4 = -5 <--- second equation checks out

The lines meet at (-21/4, -1/4)