Answer:
x = √26
Step-by-step explanation:
The Pythagorean theorem tells you the square of the hypotenuse is the sum of the squares of the sides. For the triangle on the right, the square of the hypotenuse (y) is ...
y² = 5² +7² = 25 +49 = 74
For the triangle on the left, we have ...
10² = x² +y²
100 = x² +74 . . . . . fill in the value of y² we just found
26 = x² . . . . . . subtract 74
x = √26 . . . . take the square root
