The midpoint formula states that the midpoint is equal to (x1 + x2/2, y1 + y2/2). However, in this instance, we only have to deal with the x-values because that is where our unknown variable x is. Using our formula for the x-values, we can set up the following equation:
(x + 9)/2 = 7
To solve this equation, we must first multiply both sides by 2 to get rid of the denominator on the left side of the equation.
x + 9 = 14
Next, we should subtract 9 from both sides of the equation to get the variable x alone on the left side.
x = 5
Therefore, your answer is x=5.
Hope this helps!