iGCSE Mathematics (0580) : C3.4 Interpret and obtain the equation of a straight line graph in the form y = mx + c. iGCSE Style Questions Paper 1

Question

Find the equation of line L. Give your answer in the form y = mx + c.

▶️ Answer/Explanation

Solution

Ans: y = 3x + 2

From the graph, y-intercept (c) = 2.

Slope (m) = rise/run = (5-2)/(1-0) = 3/1 = 3.

Thus equation is y = 3x + 2.

Question

(a) Find the equation of line L in the form y = mx + c

(b) On the grid, draw a line that is perpendicular to line L

▶️ Answer/Explanation

Solution

Ans:

(a) y = (1/3)x + 1 (from the graph, slope is 1/3 and y-intercept is 1)

(b) Any line with slope -3 (negative reciprocal of 1/3) would be perpendicular

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