If 3x + 5 = 20, then x =

**The reasoning** This is a **linear equation** — we need to isolate x by doing the same thing to both sides. Starting with: 3x + 5 = 20 **Step 1:** Subtract 5 from both sides to remove it from the left 3x + 5 − 5 = 20 − 5 3x = 15 **Step 2:** Divide both sides by 3 to get x alone 3x ÷ 3 = 15 ÷ 3 **x = 5** Always remember: whatever you do to one side, do to the other! **Why the wrong options tempt you** - **A) 3** — You might pick this because 3 appears in "3x", but that's the *coefficient*, not the answer - **C) 7** — Careless students sometimes do 20 ÷ 3 directly, ignoring the "+5" completely - **D) 15** — This is what 3x equals, but the question asks for x itself, not 3x **Quick takeaway** Linear equations are like unwrapping a gift: peel off layers one at a time (subtract first, then divide) until x stands alone — and always check by substituting back: 3(5) + 5 = 20 ✓