Answer:
The vertical height is 
Step-by-step explanation:
we know that
In the right triangle ABC
see the attached figure
To find the height h apply the Pythagoras Theorem

we have



substitute




Do you know how to solve this??
X=4
You have to distribute the negative sign for everything in the parentheses. After that you add x to the other side then add 8 to the opposite side to move them. Then your answer is 4.