The given expression to simplify is
[tex] 3b + 2(b-1) = 8\\
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[/tex]
open the bracket we get
[tex] 3b+2b-2=8\\
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5b-2=8\\
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\text{Add 2 on both the sides we get}\\
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5b-2+2=8+2\\
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5b=10\\
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\text{Divide on both the sides by 5 we get}\\
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b=2\\
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\text{Hence the value of }b=5\\ [/tex]