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Date May Example question Marks available 3 Reference code EXM.1.AHL.TZ0.9
Level Additional Higher Level Paper Paper 1 Time zone Time zone 0
Command term Solve Question number 9 Adapted from N/A

Question

The matrix A ( 1 2 0 3 1 1 2 2 1 )   has inverse A−1 =  ( 1 2 2 3 1 1 a 6 b ) .

Consider the simultaneous equations

x + 2 y = 7

3 x + y z = 10

2 x 2 y + z = 12

Write down the value of a .

[1]
a.i.

Write down the value of b .

[1]
a.ii.

Write these equations as a matrix equation.

[1]
b.

Solve the matrix equation.

[3]
c.

Markscheme

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

a = 4       A1 N1

[1 mark]

a.i.

b = 7       A1 N1

[1 mark]

a.ii.

EITHER

A ( x y z ) = ( 7 10 12 )       A1 N1

OR

( 1 2 0 3 1 1 2 2 1 ) ( x y z ) = ( 7 10 12 )       A1 N1

[1 mark]

b.

( x y z ) A−1  ( 7 10 12 )      (accept algebraic method)         (M1)

( x y z ) = ( 3 5 4 )      (accept x = −3, y  = 5, z  = 4)        A2    N3

[3 marks]

c.

Examiners report

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

Syllabus sections

Topic 1—Number and algebra » AHL 1.14—Introduction to matrices
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Topic 1—Number and algebra

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