Answer:
the answer to your question is x = 5
For this case, we must find an expression equivalent to:

By definition of power properties we have:

Rewriting the previous expression we have:
The "-" are canceled and we take into account that:

So:

According to one of the properties of powers of the same base, we must put the same base and add the exponents:

Answer:

Option B
Using the SSA formula:
X = SQRT ( 40^2 + 26^2 - 2*40*26*cos(65))
X = SQRT(2276 - 2080*cos(65))
X = SQRT(1396.954)
X = 37.37 = 37.4 ft.