Why the answer is B, and why the others tempt you.
## The reasoning
To solve for x, we need to get all terms with x on one side and all numbers on the other.
Starting with: **3x − 7 = 2x + 5**
**Step 1:** Subtract 2x from both sides
3x − 2x − 7 = 2x − 2x + 5
x − 7 = 5
**Step 2:** Add 7 to both sides
x − 7 + 7 = 5 + 7
x = 12
This is the **principle of maintaining equality** — whatever you do to one side, you must do to the other.
## Why the wrong options tempt you
**A) 10** — You might get this if you mistakenly did 5 + 7 = 12, then subtracted 2 somewhere. Calculation error.
**C) −12** — This happens if you moved the 7 incorrectly and forgot to change its sign, ending up with x = −12.
**D) 2** — You probably subtracted 3x from both sides instead of 2x, or mixed up the operations entirely.
## Quick takeaway
**"Collect like terms: x's on one side, numbers on the other, and always perform the SAME operation on BOTH sides."** Master this and linear equations become your friend!
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