Answer:
The value of x is 21.
Step-by-step explanation:
Since this is a right angle triangle, you can apply Pythagoras theorem, side² + side² = hypo² :
(x + 3)² + 10² = (x + 5)²
x² + 6x + 9 + 100 = x² + 10x + 25
x² + 6x + 109 - x² - 10x - 25 = 0
-4x + 84 = 0
-4x = -84
4x = 84
x = 84 ÷ 4
x = 21 units
