Answer: "x" is 4.5
Explanation:
first lets find the leg of the first right triangle using the given leg of 6 and the hypoteneuse of 9 using Pythagorean theorem a^2 + b^2 = c^2.
6^2 + b^2 = 9^2
36 + b^2 = 81
subtract 36 from both sides to isolate b
36 - 36 + b^2 = 81 - 36
simplify
b^2 = 45
take square root of both sides
=

b = 6.7
Now we can find x of the 2nd right triangle using the know hypoteneuse of 6.7 and the known leg of 5
a^2 + b^2 = c^2
5^2 = b^2 = 6.7^2
25 + b^2 = 44.9
subtract 25 from both sides to isolate b
25 - 25 + b^2 = 44.9 - 25
b^2 = 19.9
take square root of both sides
=

b= 4.5
so your answer to what is "x" is 4.5