Solve (x + 3)/2 = 8 (Step by Step)

How to solve the two-step equation (x + 3)/2 = 8, where x + 3 is divided by 2, with every step explained and a quick check of the answer.

Here 3 is added to x first, and then the whole thing is divided by 2. Undo them in reverse order: undo the divide by 2 by multiplying by 2, then take away the 3.

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Step-by-step solution

Solve (x + 3)/2 = 8

Start with the equation: (x + 3)/2 = 8.
Multiply both sides by 2 to undo the ÷ 2: ((x + 3)/2) × 2 = 8 × 2, so x + 3 = 16.
Subtract 3 from both sides to undo the + 3: x + 3 − 3 = 16 − 3, so x = 13.
Check your answer: put x = 13 back in. (13 + 3)/2 = 16/2 = 8. Both sides match, so x = 13 is correct. ✓

Answer: x = 13

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Frequently asked questions

Why multiply by 2 first?

The brackets mean the whole x + 3 is divided by 2. Dividing happened last, so it is undone first: multiply both sides by 2 to get x + 3 = 16.

Why subtract 3 instead of adding it?

The equation adds 3 to x. Subtracting 3 undoes that, so the + 3 and − 3 cancel and leave x by itself.

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