Literal Equations: Changing the Subject of a Formula — Worksheet & Memo

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Grade 10 · Equations & Inequalities

Literal Equations: Changing the Subject of a Formula

EXAM-STYLE CLASS TEST

Marks

Duration

50 minutes

Questions

Name:

Class:

Date:

Mark

/ 33

Instructions and Information

Answer ALL the questions in this question paper.
Answer QUESTION 1 by circling the letter (A–D) in the answer grid at the end of that section.
Show ALL calculations clearly.
Show all units where applicable.
Number the answers correctly according to the numbering system used in this question paper.
A non-programmable calculator may be used, unless stated otherwise.
Write neatly and legibly.

Question 1

[10 MARKS]

Four options are given as possible answers to the following questions. Choose the correct answer and circle the letter (A–D) in the grid at the end of this section. If you want to change your choice, put a cross through the wrong letter and circle your new choice.

1.1
Make x the subject of y = mx + c.
(1)
A)y − cm
B)ym − c
C)y + cm
D)y − c − m
1.2
Make r the subject of A = πr².
(1)
A)√(A ÷ π)
B)A ÷ π
C)√(Aπ)
D)A² ÷ π
1.3
Make h the subject of V = 13πr²h.
(1)
A)3Vπr²
B)V3πr²
C)3Vπr
D)Vπr²
1.4
Make b the subject of P = 2(l + b).
(1)
A)P − 2l2
B)P2 − 2l
C)P − 2l
D)P2l
1.5
Make x the subject of ax + b = cx + d.
(1)
A)d − ba − c
B)d + ba + c
C)b − da − c
D)d − bc − a
1.6
Make a the subject of v² = u² + 2as.
(1)
A)v² − u²2s
B)v² + u²2s
C)v − u2s
D)v² − u²s
1.7
Make C the subject of F = 95C + 32.
(1)
A)59(F − 32)
B)95(F − 32)
C)59F − 32
D)59(F + 32)
1.8
Make n the subject of T_n = a + (n − 1)d.
(1)
A)T_n − ad + 1
B)T_n − ad
C)T_n − a + 1d
D)T_n + ad + 1
1.9
Make x the subject of xa + xb = 1.
(1)
A)aba + b
B)a + bab
C)ab
D)aba − b
1.10
Make y the subject of 3x − 2y = 12.
(1)
A)3x − 122
B)12 − 3x2
C)3x + 122
D)3x − 12

Answer grid — circle your answers for Question 1

1.1	A	B	C	D
1.2	A	B	C	D
1.3	A	B	C	D
1.4	A	B	C	D
1.5	A	B	C	D
1.6	A	B	C	D
1.7	A	B	C	D
1.8	A	B	C	D
1.9	A	B	C	D
1.10	A	B	C	D

Question 2

[12 MARKS]

Change the subject of each formula as instructed. Show ALL your steps.

2.1
Make x the subject of y = 2x + 6.
(3)
2.2
Make r the subject of V = πr²h, and hence calculate r if V = 500, h = 10 and π ≈ 3,14, correct to TWO decimal places.
(5)
2.3
Make x the subject of ax = bx + c.
(4)

Question 3

[11 MARKS]

Answer the questions below.

3.1
Make n the subject of A = P(1 + in).
(4)
3.2
Hence determine how many years it takes R1 000 to grow to R1 400 at 10% p.a. simple interest.
(4)
3.3
Explain, in words, the method used when the required letter appears TWICE.
(3)

TOTAL: 33 marks

This question paper consists of 3 questions.