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Date November 2020 Marks available 2 Reference code 20N.1.SL.TZ0.T_11
Level Standard Level Paper Paper 1 Time zone Time zone 0
Command term Write down Question number T_11 Adapted from N/A

Question

The diagram shows the graph of the quadratic function f(x)=ax2+bx+c , with vertex 2, 10.

The equation f(x)=k has two solutions. One of these solutions is x=2.

Write down the other solution of f(x)=k.

[2]
a.

Complete the table below placing a tick (✔) to show whether the unknown parameters a and b are positive, zero or negative. The row for c has been completed as an example.

[2]
b.

State the values of x for which f(x) is decreasing.

[2]
c.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

x= -2-4  OR  x= -2-2--2      (M1)


Note:
Award (M1) for correct calculation of the left symmetrical point.


x= -6      (A1)   (C2)


[2 marks]

a.

      (A1)(A1)   (C2)


Note:
Award (A1) for each correct row.


[2 marks]

b.

x>-2  OR  x-2      (A1)(A1)   (C2)


Note:
Award (A1) for -2 seen as part of an inequality, (A1) for completely correct notation. Award (A1)(A1) for correct equivalent statement in words, for example “decreasing when x is greater than negative 2”.


[2 marks]

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Topic 2—Functions » SL 2.5—Modelling functions
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Topic 2—Functions

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