Answer:
x = 2√13
Step-by-step explanation:
First, we can put out a lot of equations to see if we can make a system:
x² = y² + 4², x² + z² = 13², xz = 13y, y² + 9² = z²
Substitute 4 into 1: x² = (z² - 9²) + 4²
System 2 and substitution: x² + z² = 169, x² - z² = -65
Elimination: 2x² = 104
Divide: x² = 52
Square root: x = √52 = 2√13
