What is the x-coordinate of the solution for the system of equations?
y−x=9
10+2x=−2y
+37099 Re-arrange the first equation to get y = 9+x Substitute this in to the second equation
10 + 2x = -2(9+x) Solve for 'x'
10 + 2x = -18 - 2x add 2x to both sides of the equation
10 + 4x = -18 Subtract 10 from both sides
4x = -28
x = -7 (and y= 9+x = 2)
