Answer:
x=5
From the dashed lines on the two sides of this triangle, we can see that these two sides are congruent, or equal, to each other.
In geometry, if a triangle has two congruent sides, then we can call it a isosceles triangle.
In an isosceles triangle, the corners opposite the congruent sides are also congruent, meaning, that the angle measures of this triangle are: 88, 9x+1, and 9x+1.
We also know that angles in a triangle add up to 180 degrees.
So, we have: 88+(9x+1)+(9x+1) = 180
Simplifying: 18x + 2 = 92
Solving: 18x = 90, so x=5
Hope this helps!