does anyone know the answer?

Answer:
x = 3[tex]\sqrt{2}[/tex]
Step-by-step explanation:
Since the triangle is isosceles then the 2 legs are congruent, both x
Using Pythagoras' identity in the right triangle
x² + x² = 6²
2x² = 36 ( divide both sides by 2 )
x² = 18 ( take square root of both sides )
x = [tex]\sqrt{18}[/tex] = [tex]\sqrt{9(2)}[/tex] = [tex]\sqrt{9}[/tex] × [tex]\sqrt{2}[/tex] = 3[tex]\sqrt{2}[/tex]