Answer:
x=82 hope this helps! 
Explanation:
2+90−=10
2+90−x=102+90-x=102+90−x=10
Solve
1
Add the numbers
2+90−=10
92−=10
2
Rearrange terms
3
Subtract 
92
929292
 from both sides of the equation
4
Simplify
5
Divide both sides of the equation by the same term
6
Simplify
Solution
2+90−=10
2+90−x=102+90-x=102+90−x=10
Solve
1
Add the numbers
2+90−=10
92−=10
2
Rearrange terms
3
Subtract 
92
929292
 from both sides of the equation
4
Simplify
5
Divide both sides of the equation by the same term
6
Simplify
Solution
=82