Unit 3
4 marks · Normal(a) Solve for x:
(b) Write down the value of x if .
(c) The line y = 2x + 1 passes through the point (p, 11). Write down the value of p.
Solve for x:
What is x if ?
The line y = 2x + 1 passes through the point (p, 11). Write down the value of p.
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) 16 · must show 16
(b) x = 2 or -2 · must show 2, -2
(c) 5 · must show 5
Common mistakes: Not rearranging equation correctly; Forgetting ± in x² equations
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Subtracts 3 on both sides to get x/4 = 4.
A1 (a) · 1 mark · Gets x = 16.
M2 (b) · 1 mark · Divides both sides by 2 to get x² = 4, then square roots both sides.
A2 (c) · 1 mark · Sets 11 = 2p + 1 -> p = 5.
Worked solution
(a) x/4 + 3 = 7 -> x/4 = 4 -> x = 16.
(b) 2x^2=8 -> x^2=4 -> x=2 or -2.
(c) 11 = 2p + 1 -> 10 = 2p -> p = 5.