Short leg = x-6m
Longer leg =x
Hypotenuse = x+6m
x² + (x-6)² =(x+6)²
x² + x²-12x+36 = x²+12x+36
2x²-12x+36= x² +12x+36
2x²-12x+36-36= x² +12x+36-36
2x² - 12x-12x = x²+12x-12x
2x² -24x-x² = x²-x²
x² -24x = 0
x(x-24)=0
x = 24
Short leg = 24-6m = 18
Longer leg =24
Hypotenuse = 24+6m=30
Check
a² + b² = c²
18² +24² =30²
324 +576 = 900
900=900