# Rearranging a formula method. Express x in terms of y (1 inverse only)

In this article we shall be covering some more worked example on rearranging a formula (making subjects). All the examples below only require one inverse to solve. All you need to do is to apply the inverse operations to both sides of the formula (just like when you solve an equation). Also before you start rearranging the formula switch the left hand side and right hand side of the formula over as this makes the rearranging process a whole lot easier.

Question 1. Rearrange the formula so that x is expressed in terms of y and z.

y = x + 7z

This means you need a formula for x

Begin the process by swapping the two sides of your formula.

x + 7z = y

Now on the left hand side 7z is being added to x. So take 7z off both sides.

x = y – 7z.

Question 2. Rearrange the formula so that x is expressed in terms of y and z.

y = x – 3z

Begin the process by swapping the two sides of your formula.

x – 3z = y

Next add 3z to both sides of you formula (as you are taking 3z off x on the LHS)

Therefore, x = y + 3z.

Question 3. Express x in terms of w and y.

y = x/w

Begin the process by swapping the two sides of your formula.

x/w = y

Times both sides of the formula by w (the opposite to divide by w)

x = wy

Question 4. Express x in terms of a and b.

b = 7ax

Begin the process by swapping the two sides of your formula.

7ax = b

Divide both sides of the formula by 7a (the opposite to times by 7a)

x = b/7a

For some harder questions on rearranging formula when you require one inverse operation then click here.

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