Graphs 1

4 marks · Hard

The point Q has coordinates (k, 12) and lies on the line y = 3x + 6.

(a)

Find the value of k.

[2 marks]

(b)

The point R lies on the same line and has x-coordinate –2. Find the y-coordinate of R.

[2 marks]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

(a) 2

(b) 0

Common mistakes: Algebraic errors; Sign errors

Show mark scheme and worked solution

Marking points

M1 (a) · 1 mark · Sets y = 12 and substitutes in equation or rearranges equation correctly.

A1 (a) · 1 mark · Correct value k = 2.

M2 (b) · 1 mark · Substitutes x = –2 into equation. (follow-through)

A2 (b) · 1 mark · Correct value y = 0. (follow-through)

Worked solution

a) For point Q, y = 12:

b) For point R, x = –2: