Maths · Topic 1: Year 10

Equations and inequalities

Solving linear inequalities, quadratic equations by factorising, the formula and completing the square, and solving simultaneous equations, including linear with quadratic.

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Key terms in this chapter

All 42, gathered from every lesson.

Inequality
A statement that compares two values using \(<\), \(>\), \(\le\) or \(\ge\).
Integer
A whole number, positive, negative or zero.
Solution set
All the values that make an inequality true.
Boundary line
The line that separates a region on a graph.
Region
An area of a graph that satisfies one or more inequalities.
Strict inequality
One with \(<\) or \(>\), not including the boundary.
Quadratic equation
An equation whose highest power is \(x^2\).
Root
A solution of an equation; where a graph crosses the x-axis.
Factorise
Write as a product of brackets.
Null factor law
If \(ab = 0\), then \(a = 0\) or \(b = 0\).
Difference of two squares
\(a^2 - b^2 = (a - b)(a + b)\).
Perfect square
A quadratic that is a bracket squared.
Coefficient
The number multiplying a variable, such as the 2 in \(2x^2\).
Quadratic formula
\(x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}\).
Discriminant
The expression \(b^2 - 4ac\) under the square root.
Surd
A root that cannot be simplified to a whole number, such as \(\sqrt{7}\).
Root
A solution of an equation.
Substitute
Replace letters with numbers.
Completing the square
Rewriting a quadratic as a squared bracket plus a constant.
Turning point
The lowest or highest point of a quadratic graph.
Minimum value
The smallest value a function can take.
Line of symmetry
The vertical line through the turning point.
Surd
A root left in exact form, such as \(\sqrt{11}\).
Coefficient
The number multiplying a variable.
Simultaneous equations
Two or more equations that are true at the same time.
Unknown
A letter standing for a number to be found.
Elimination
Removing one unknown by adding or subtracting equations.
Substitution
Replacing an unknown with an expression.
Solution
The pair of values that satisfies both equations.
Coefficient
The number multiplying an unknown.
Simultaneous equations
Equations that must both be true for the same unknown values.
Elimination
Removing an unknown by adding or subtracting.
Lowest common multiple
The smallest number that is a multiple of two numbers.
Coefficient
The number multiplying an unknown.
Substitute
Replace an unknown by its value.
Check
Put the answers back into both equations.
Tangent
A line that touches a curve at exactly one point.
Repeated root
A solution that occurs twice, such as \(x = 1\) in \((x - 1)^2 = 0\).
Intersection
A point where a line and a curve meet.
Substitution
Replacing a letter with an expression.
Circle equation
\(x^2 + y^2 = r^2\) for a circle centred on the origin.
Discriminant
\(b^2 - 4ac\); it shows the number of real roots.