Can you show me the steps that you took to get the answer for this question?

X=47 because m1+m2=90°

The answer is C.
If measure of 1 + measure of 2 = 90
And measure of 1 = x
And measure of 2 = x - 4
You would have the equation of
X + X - 4 = 90
So then you combine like terms
2x - 4 = 90
Then you add 4 on both sides
2x - 4 = 90
+ 4 + 4
2x = 94
Then you divide by 2 to get x alone
And x = 47

Horizontal change or the change of x