Gradient & equation of a line: IGCSE Mathematics questions with answers
Free Gradient & equation of a line questions for IGCSE Mathematics (0580), part of Coordinate geometry. Each question has the answer and the marking points an examiner would look for.
The line L has gradient 2 and passes through the point (2, 9). L crosses the x-axis at A and the y-axis at B. O is the origin. Find the area of triangle OAB.
[4]
Show answers and mark scheme
Part
Answer and marking points
Marks
254
y = 2x + 5 M1 B = (0, 5), A = (−52, 0) A1 ½ × base × height M1 254A1
4
Question 2Structured · 11 marksA* challenge
The line L has equation y = 2x. A is the point (1, 7) and B is the point (3, 9). A and B are on the same side of L.
(a)
Find the coordinates of the point on L that is nearest to A, and the exact shortest distance from A to L.
[3]
(b)
P is a point on L. Find the coordinates of P for which AP + PB is as small as possible, and the exact value of this least distance.
[5]
(c)
Q is a point on L. Find the coordinates of Q for which QA − QB is as large as possible, and the exact value of this greatest difference.
[3]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
(3, 6); √5
line through A perpendicular to L: y − 7 = −½(x − 1) M1 meets y = 2x at (3, 6) A1 √(22 + 12) = √5 A1
3
(b)
P = (3.75, 7.5); least AP + PB = 2√5
reflects A in L: A′ = (5, 5) M1 A′ = 2(3, 6) − (1, 7) A1 least AP + PB is when P is on A′B: y = −2x + 15 M1 P = (3.75, 7.5) A1 A′B = √(22 + 42) = 2√5 A1
5
(c)
Q = (6, 12); 2√2
QA − QB ≤ AB, with equality when Q, B, A are collinear: line AB is y = x + 6 M1 Q = (6, 12) A1 AB = 2√2 A1
3
Question 3Structured · 4 marks
The equation of a line is 3x + 6y = 36.
(a)
Find the gradient of the line.
[2]
(b)
Find the coordinates of the points where the line crosses the x-axis and the y-axis.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
−12
rearranges to y = … M1 −12A1
2
(b)
(12, 0) and (0, 6)
(12, 0) B1 (0, 6) B1
2
Question 4Structured · 6 marks
The diagram shows the line L.
Fig. 4.1
(a)
Find the gradient of line L.
[2]
(b)
Find the equation of line L in the form y = mx + c.
[2]
(c)
Find the equation of the line parallel to L that passes through the point (−6, 3).
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
−12
−48 using two points on the line M1 −12A1
2
(b)
y = −12x − 1
y = −12x − 1 B2 B1 for correct gradient or correct intercept in y = mx + c
2
(c)
y = −12x
3 = −12 × −6 + c M1 y = −12x A1
2
Question 5Structured · 4 marksA* challenge
The line L has gradient −1 and passes through the point (2, −5). L crosses the x-axis at A and the y-axis at B. O is the origin. Find the area of triangle OAB.
[4]
Show answers and mark scheme
Part
Answer and marking points
Marks
92
y = −x − 3 M1 B = (0, −3), A = (−3, 0) A1 ½ × base × height M1 92A1
4
Question 6Structured · 4 marks
The equation of a line is 2x + 3y = 12.
(a)
Find the gradient of the line.
[2]
(b)
Find the coordinates of the points where the line crosses the x-axis and the y-axis.
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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in