Solving equations is just 'unwrapping' a variable to get it by itself. If you're stuck on where to start, remember that we solve equations by doing the order of operations (PEMDAS) in reverse.

We call this SADMEP:

Whatever you do to the left side, you must do to the right side. No exceptions.

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Step 1: Undo Addition/Subtraction (The 'S/A' in SADMEP) We see a $-7$. To undo it, we add $7$ to both sides. $4x - 7 + 7 = 13 + 7$$4x = 20$

Step 2: Undo Multiplication/Division (The 'D/M' in SADMEP)$x$ is being multiplied by $4$. To undo it, we divide both sides by $4$. $\frac{4x}{4} = \frac{20}{4}$$x = 5$

The Pro-Tip Check: Always plug your answer back into the original. $4(5) - 7 \rightarrow 20 - 7 = 13$. It matches. Move on to the next one.

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Use this to track where your 'mental glitches' happen. Most students lose points on negative signs or forgetting to do the same thing to both sides.