Cambridge IGCSE Maths 0580 Equation of a Straight Line Questions
Equation of a Straight Line questions with worked answers for Cambridge IGCSE Mathematics (0580). Each question says whether it is Core or Extended and whether it is for a calculator or non-calculator paper. Try each one before you open the answer.
3.5 Equations of linear graphsCoreExtended Interpret and find the equation of a straight line in the forms y = mx + c and x = k. Extended also: Use lines in other forms, e.g. ax + by = c, and find the equation of a line through two points.
Summarised in our own words: check the exact wording in the official 0580 syllabus.
Equation of a Straight Line questions: Core
For everyone: Core students (Papers 1 and 3) and Extended students (Papers 2 and 4).
Question 1 Core non-calculator · easy
The equation of a line is \(y = 9 - 5x\). Write down (a) its gradient (b) the coordinates of the point where it crosses the \(y\)-axis.
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Rewrite as \(y = -5x + 9\). In \(y = mx + c\), \(m\) is the gradient and \(c\) is the \(y\)-intercept.
Answer: (a) \(-5\) (b) \((0, 9)\)
Question 2 Core non-calculator · easy
A line has gradient \(-2\) and crosses the \(y\)-axis at \((0, 5)\). Write down its equation.
Show the worked answer
\(m = -2\) and \(c = 5\).
Answer: \(y = -2x + 5\)
Question 3 Core non-calculator · easy
Write down the equation of the vertical line through \((-4, 6)\).
Show the worked answer
Every point on a vertical line has the same \(x\)-coordinate.
Answer: \(x = -4\)
Question 4 Core calculator · easy · 2 marks
Write down the equation of the straight line with
(a) gradient 2 and \(y\)-intercept 5
(b) gradient \(-\frac{1}{2}\) and \(y\)-intercept 3.
The graph of a straight line is drawn on a grid. The line passes through the grid points \((1, 4)\) and \((3, 10)\). Find the equation of the line in the form \(y = mx + c\).
Show the answer and mark scheme
M1 gradient (10 − 4) ÷ (3 − 1) = 3
M1 4 = 3 × 1 + c
A1 y = 3x + 1
Answer: \(y = 3x + 1\)
Question 6 Core calculator · medium · 2 marks
Write \(2y = 6x - 8\) in the form \(y = mx + c\) and write down the gradient.
Show the answer and mark scheme
B1 y = 3x − 4
B1 gradient 3
Answer: \(y = 3x - 4\), gradient \(3\)
Equation of a Straight Line questions: Extended
Extended content, for Papers 2 and 4. Core students can skip these.
Question 7 Extended non-calculator · medium
Find the gradient and the \(y\)-intercept of the line \(2y = 6x + 10\).
Show the worked answer
Divide by \(2\): \(y = 3x + 5\).
Answer: Gradient \(3\), \(y\)-intercept \(5\)
Question 8 Extended non-calculator · medium
Find the gradient of the line \(3x + 4y = 12\).
Show the worked answer
\(4y = -3x + 12\), so \(y = -\frac{3}{4}x + 3\).
Answer: \(-\frac{3}{4}\)
Question 9 Extended non-calculator · medium
Find the equation of the line through \((1, 4)\) and \((3, 10)\).
Show the worked answer
Gradient \(= \frac{10 - 4}{3 - 1} = 3\).
\(4 = 3 \times 1 + c\), so \(c = 1\).
Answer: \(y = 3x + 1\)
Question 10 Extended non-calculator · hard
Find the equation of the line through \((-2, 7)\) and \((4, -5)\).
Every question on this page is original, written for IGCSE Math Revision rather than taken from Cambridge papers, and each answer was re-solved independently before publishing. Questions with a mark scheme come from our 0580 practice bank (M method, A accuracy, B independent marks).
Which Cambridge 0580 papers can test equation of a straight line?
Equation of a Straight Line is on both tiers (syllabus 3.5), so it can come up on Core Papers 1 (non-calculator) and 3 (calculator), and Extended Papers 2 (non-calculator) and 4 (calculator). Extended candidates also need the Extended parts listed on this page. Half of each tier's marks are on a non-calculator paper, so practise the non-calculator questions without one.
Are these Cambridge past-paper questions?
No. Every question here was written for IGCSE Math Revision in the style of the 0580 papers, and each answer was checked independently before publishing. For real exam practice, use the Cambridge past papers linked from our 0580 past papers page.
Where can I practise more equation of a straight line questions?
In the 0580 practice for topic 3 (Coordinate geometry), where every question is marked and tagged Core or Extended. Practice is part of the IGCSE plan, with a free preview; the questions on this page are free.