From the image you provided, the problem contains the following values and symbols:

• $\mu = 0.045 \, \text{kg/m}$ (linear mass density of the string)
• $m = 0.015 \, \text{kg} = 15 \, \text{g}$ (mass)
• $n = 4$ (harmonic number)
• $f = 130 \, \text{Hz}$ (frequency of the wave)
• $T = ?$ (tension in the string)
• $L = ?$ (length of the string)

This appears to be a problem involving the frequency of a standing wave on a string. The relationship between the tension $T$, linear density $\mu$, frequency $f$, and length $L$ is given by the formula for the frequency of the $n$-th harmonic:

$f = \frac{n}{2L} \sqrt{\frac{T}{\mu}}$

We'll need to solve this for $T$ (tension) and $L$ (length). Let's work step by step to solve for these unknowns.

Would you like me to proceed with the calculations?