# 3.1 Algebraic Formulae

3.1 Algebraic Formulae

3.1.1 Variables and Constant
1. A variable is a quantity without a fixed value.
2. A constant is a quantity with a fixed value.

3.1.2 Concept of Formulae
1. An algebraic formula is an equation which shows the relationship between several variables and/ or constant.
2. The subject of an algebraic formula is a linear variable expressed in terms of the other variables.

Example 1:

Solution:
$\begin{array}{l}y=\frac{2-3x}{x}\\ xy=2-3x\\ xy+3x=2\\ x\left(y+3\right)=2\\ x=\frac{2}{y+3}\end{array}$

Example 2:

Solution:
$\begin{array}{l}s=\frac{{p}^{2}-{q}^{2}}{2u}\\ 2us={p}^{2}-{q}^{2}\\ {p}^{2}=2us+{q}^{2}\\ p=\sqrt{2us+{q}^{2}}\end{array}$

### 2 thoughts on “3.1 Algebraic Formulae”

1. On question, it’s 2u. But the solution is 2r? Hopefully, ya fix it, thank you

• Thanks for pointing out our mistake.