Algebraalgebrarearranging formulaechanging the subject
AQA GCSE · Question 12.2 · Algebra
Rearrange y = w - 1 to make w the subject.
How to approach this question
1. The equation is y = w - 1.
2. To make w the subject, we need to isolate it on one side of the equation.
3. Currently, 1 is being subtracted from w.
4. To undo the subtraction, we perform the inverse operation, which is to add 1.
5. Add 1 to both sides of the equation: y + 1 = w - 1 + 1.
6. This simplifies to y + 1 = w.
7. It is conventional to write the subject on the left: w = y + 1.
Full Answer
w = y + 1
We are given the equation y = w - 1.
Our goal is to make w the subject, which means we want to have w on its own on one side of the equals sign.
To get w by itself, we need to eliminate the "- 1" that is on the same side.
The opposite of subtracting 1 is adding 1.
We must do the same thing to both sides of the equation to keep it balanced.
Add 1 to both sides:
y + 1 = w - 1 + 1
y + 1 = w
We can write this with the subject on the left-hand side:
w = y + 1
Common mistakes
✗ Subtracting 1 from both sides instead of adding.
✗ Moving the 1 but not changing the sign.
Expert