You mean, what is this number?
we can rephrase it like this: the sum of a number x and 8 is 15
which is:
x+8=15
we subtract 8 from both sides and we get
x=7
so the answer is 7.
Answer and Explanation:
Since this is an isosceles right triangle, you can use the ratio of side lengths specific to this type of triangle where both legs are the hypotenuse over root 2:
u = v = 164√2 / √2 = 164
so:
u = 164
v = 164