We can solve for x by using trigonometric ratios (sin, cos, and tan)
We need to apply the appropriate ratio that uses the two sides 8 and 10 from the perspective of x. See attached image for information about ratios. (Source: Math is Fun)
The tangent ratio is opposite divided by adjacent. It will relate x to the two sides. So we would write
tan(x) = ⁸⁄₁₀
Then we simplify and move the tan to the other side by multiplying both sides by the inverse of tan (since you cannot divide by tan)
tan(x) = ⅘
x = tan⁻¹(⅘)
Then we can use a calculator to evaluate x
If you want to find y, now that you have two angles of the triangle, you can find the sum of 90 + x and subtract that from 180 (since all angles of a triangle add up to 180) to find y.