Answer:

Step-by-step explanation:
we know that
The formula of law of cosines is equal to

where
a, b and c are sides. C is the angle opposite side c
In this problem we have

substitute the given values






So it would be 8/40. And in its simplest terms would be 1/5
ANSWER
y=x
y=x³
EXPLANATION
A function, f(x) has an inverse if and only if

Thus, the function is one to one.
For y=x or


Hence this function has an inverse.
For the function y=x² or f(x)=x².

This function has no inverse on the entire real numbers.
For the function y=x³ or f(x)=x³

This function also has an inverse.
For y=x⁴ or f(x) =x⁴

This function has no inverse over the entire real numbers.
Volume is the product of the three dimensions...
V=xyz in this case:
V=3*10*5
V=150 yd^3
5x2 I think I hope you get it right :( sorry if I was wrong