Answer: x = 7
Step-by-step explanation:
1) This special right triangle is the isosceles right triangle: 45°-45°-90°.
It is an isosceles right triangle, then x = 7.
2) For these the isosceles right triangle you have: hypotenuse = leg length × √2.
You can prove that using Pythagoras: hypotenuse² = side² + side² = 2×side² ⇒ hypotenuse.
3) Therefore: x = 7 and y = 7√2