Answer:
x = 4sqrt(2)
Explanation:
Since this is a right triangle, we can use the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
x^2 + 7^2 = 9^2
x^2 +49 = 81
Subtract 49 from each side
x^2 = 81-49
x^2 =32
Take the square root of each side
sqrt(x^2) = sqrt(32)
x = sqrt( 16*2)
x = sqrt(16) sqrt(2)
x = 4sqrt(2)