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