5. Formulas and Literal Equations

It is very common in science and engineering to have a formula and we need to re-arrange it so that some variable that is originally on the right hand side becomes the subject of the formula.

In this section, we are finding an expression (involving letters and numbers) which is equal to a particular given letter. [Hence literal equation].

We simply solve the equation like we did in the previous Solving Equations section, by balancing both sides.

Example 1

We recall the area of a rectangle with width w and height h.

A = w × h

area

Express the formula in terms of the height.

Answer


Example 2

The area of a circle is given by

A = π r2

Solve for r.

Answer


Example 3

Solve A1 = A(M + 1) for M.

Answer


Example 4

Solve the following for T1:

T = 3(T2 − T1)

Answer




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