X=y+10 and x=2y+3
solve by substitution
needing x and y

The two equations given in the question are
x = y + 10
And
x = 2y + 3
Now let us substitute the value of x in the second equation with that of the first equation. We get
x = 2y + 3
y + 10 = 2y + 3
y - 2y = 3 - 10
- y = - 7
y = 7
Now putting the value of y in the first equation, we get
x = y + 10
   = 7 + 10
   = 17
So the value of x comes out to be 17 and the value of y comes out to be 7.