Algebraic Formulae

3.1

Algebraic Formulae

	Definition

	It is written in the form of an equation that combines an algebraic expression using addition, subtraction, multiplication or division.

Forming formula

Example

\(y= 3x -5\)

\(w = \dfrac{6-v}{v}\)

\(L = \dfrac{1}{2} th\)

\(A = \pi r^2\)

Changing the subject of the formula

Tips

The subject of the formula is represented by a letter.
The subject of the formula should be on the left side of the equation.

Example

Determining the value of the variable

Tips

The value of a variable in the subject of the formula can be obtained when the value of other variables is given.

Example

Given \(Q= \dfrac{2v}{-v +u}\), calculate the value of \(u\), where \(v=2, Q= 4\).

\(\begin{aligned} \\\space4 &= \dfrac{2(2)}{-2 + u} \\\\ 4 (-2 +u) &= 4 \\\\ -8 + 4u &= 4 \\\\ 4u &= 12 \\\\ u &= \dfrac{12}{4} \\\\ u &=3. \end{aligned}\)

Solving problems

Tips

It involves changing the subject of a formula, a combination of basic mathematical operations, square and square root.