Final answer:
The length of SU is 3.
Step-by-step explanation:
To find the value of SU, we can set up an equation where TU = SU. Since T is the midpoint of SU, the lengths of SU and TU should be equal. Therefore, we can set up the equation 3x + 3 = x + 3 and solve for x. Subtracting x from both sides gives us 2x + 3 = 3, and by subtracting 3 from both sides, we find that 2x = 0. Solving for x, we see that x = 0. Plugging this back into the original equation, we find that SU = 3(0) + 3 = 3.
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