Answer:
t=-2
Step-by-step explanation:
(t+9)20=140
Distribute the 20
20t +180 = 140
Subtract 180 from each side
20t +180-180 = 140-180
20t = -40
Divide by 20
20t/20 = -40/20
t=-2

Actually Welcome to the Concept of the Inverse of real function.
Let's consider here, g(n) = y ,
so we get as,
![y = \sqrt[3]{ \frac{n - 1}{2} }](https://tex.z-dn.net/?f=y%20%3D%20%20%5Csqrt%5B3%5D%7B%20%5Cfrac%7Bn%20-%201%7D%7B2%7D%20%7D%20)
no, cubing the power both side we get as,
=>

now,

so finally, we get as,
=>

hence,here, n = inverse of the g(n) function.
so,
g^-1 (n) = 2y^3+1.
To calculate hypothenuse you use the formula a^2+b^2=c^2 where c is the length of the hypothenuse.
1. 5^2+7^2=c^2
2.25+49=74
3. Now you will square root the 74
4. The hypothenuse is equal to 8.6