Equations with negative numbers
Solve 17 − 5x = −38
The aim is to get x on its own. Whatever we do to one side, we do to the other, so the equation stays balanced. This one takes 3 steps.
- 17 − 5x = −38The question.
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Step 1: Add 5x on both sides +5x
On the left, the x term is −5x, which is negative. Add 5x to both sides, so the x term is positive.
17 = −38 + 5xOn the left, the 5x cancels out. Now there’s no x on the left.
− 5x is undone by + 5x.
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Step 2: Add 38 on both sides +38
On the right, the x part has − 38 with it. Add 38 to both sides to get rid of it.
55 = 5xOn the right, the 38 cancels out.
− 38 is undone by + 38.
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Step 3: Divide by 5 on both sides ÷5
5x means 5 × x. Divide both sides by 5 to get x on its own.
11 = xx is on its own. x = 11.
Multiplying is undone by dividing.
Answer: x = 11
Check it
Put x = 11 back into the question. If both sides come to the same number, the answer is right.
Left side: 17 − 5x → 17 − 55 = −38
Right side: −38 → −38
✓ Both sides are −38, so x = 11 is right.
Now try it yourself
Solve this one in Algebra Balance. You choose each step, and it explains what happened, with hints if you get stuck.
Practise this in Algebra Balance