Final answer:
To find TU in rhombus QRST, substitute the value of Z from the first equation into the second equation, which gives us TU = 3z - 42.
Step-by-step explanation:
In the given rhombus QRST, we are given that RU = 3z - 42 and TU = Z. To find TU, we need to substitute the value of Z from the first equation into the second equation, which gives us TU = 3z - 42.