Answer: 40
Step-by-step explanation: When you're asked to solve for x in an equation, what you're really being asked to do is get x by itself on one side of the equation.
In this problem since 10 is being added to x, in order to get x by itself, we must subtract 10 from the left side of the equation and when we subtract 10 from the left side of the equation, remember that we must also subtract 10 from the right side of the equation.
So on the left, 10 - 10 cancels out and
on the right, 50 - 10 simplifies to 40.
So x = 40.