Year 8 Unit 9: Solving Equations, Inequalities & Quadratics

Vocabulary and terminology coverage for Year 8 algebraic concepts including linear equations, inequalities, quadratics, and rearranging formulas.

Unknown

A letter which represents a number we do not know the value of.

Terms

The numbers and letters in the expression or equation.

Inverse

The operation which will do the opposite.

Possible answer types

Answers for equations can be integers, decimals, fractions, or negatives.

Angles in a triangle

In geometry, these sum to $180$.

Inequality

Shows the range of numbers that satisfy a rule.

$$x < 2$$

$x$ is less than $2$.

$$x \le 2$$

$x$ is less than or equal to $2$, meaning it can be equal to $2$.

$$x > 2$$

$x$ is greater than $2$.

$$x \ge 2$$

$x$ is greater than or equal to $2$, meaning it can be equal to $2$.

Open circle (Number Line)

Used on a number line for less than ($<$) or greater than ($>$) to show a value cannot be equaled.

Closed circle (Number Line)

Used on a number line for less than or equal to ($\le$) or greater than or equal to ($\ge$) to show a value can be equaled.

Factorising (Quadratics)

A method to solve quadratic equations by putting the expression into brackets first.

Quadratic Equation

An equation in the form $x^2 + bx + c = 0$.

Changing the subject of a formula

Working with inverse operations to isolate a highlighted variable.

Rearranging

The process of undoing operations starting from the last one to isolate a variable.