can someone please explain, i really need help

Answer:
x = 42.5
Step-by-step explanation:
A triangle formed inside of a circle using the diameter as one of its side lengths is a right triangle
The right angle would be the angle opposite of the diameter (∠C)
A right angle has a measure of 90°
That being said we use this equation to solve for x
90 = 2x + 5
step 1 subtract 5 from each side
90 - 5 = 85
5 - 5 cancels out
now we have 85 = 2x
step 2 divide each side by 2
85/2=42.5
2x/2=x
we're left with x = 42.5