In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
y=2x+9 eq. 1
y=5x+10 eq. 2
y = ?
x = ?
Step 02:
substitution method
eq.1 in eq.2
2x+9=5x+10
2x - 5x = 10 - 9
-3x = 1
x = 1 / (-3)
x = - 1 / 3
x in eq. 1
y=2(-1/3) + 9

The answer is:
x = - 1 /3
y = 25 / 3