Answer: x = 3
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Explanation:
T is the midpoint of SU, so point T cuts segment SU into two equal halves. Those two halves being ST and TU, therefore, ST = TU
ST = TU
8x+11 = 12x-1 ... substitution
8x+11-8x = 12x-1-8x ... subtract 8x from both sides
11 = 4x-1
11+1 = 4x-1+1 .... add 1 to both sides
12 = 4x
4x = 12
4x/4 = 12/4 .... divide both sides by 4
x = 3
As a check, plug x = 3 into each equation below
ST = 8x+11 = 8*3+11 = 24+11 = 35
TU = 12x-1 = 12*3-1 = 36-1 = 35
Each piece ST and TU is 35 units long. So this confirms we have the right answer.