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4.02 Substitution

Worksheet
Substitution into expressions
1

Evaluate:

a
m + 5 when m = 7
b
9 + m when m = 3
c
x - 2 if x = 8
d
8 - c when c = 1
e
6 x + 4 when x = 9
f
3 x^{2} - 7 x - 4 when x = 3
g
- 2 x^{3} + 4 x^{2} + 8 x + 4 when x = - 1
2

Evaluate:

a
\dfrac{x + 6}{x + 5} when x = 8
b
\dfrac{4 y - 1}{y - 1} when y = 6
c
\dfrac{z^{3}}{z^{2} - 6} when z = 4
d
\dfrac{y}{y^{3} - 43} when y = 4
e
\dfrac{x^{2} + 3 x + 2}{x^{2} - 4 x - 12} when x = 7
f
\dfrac{3 x + 2}{x^{2} - 4 x - 12} when x = 7
3

Evaluate:

a
7 x + 5 when x = \dfrac{1}{7}
b
4 x^{2} + 7 x + 3 when x = \dfrac{1}{4}
c
4 x^{3} + 10 x^{2} when x = \dfrac{1}{2}
d
\dfrac{2 x - 9}{5} when x = \dfrac{29}{2}
e
\dfrac{11 x + 5}{7 x + 9} when x = - \dfrac{13}{3}
4

Evaluate y + 5 if:

a
y = 3
b
y = 6
5

Evaluate u + v if:

a
u = 7 and v = 3.
b
u = 3 and v = 16.
6

Evaluate a + b when a = 5 and b = 1.1.

7

Evaluate a - b when a = 9 and b = 5.

8

Evaluate u + v + 25 if u = 32 and v = 48.

9

Evaluate a + b + c if a = 10, b = 15, and c = 11.

10

If a = 2, b = 7 and c = - 8, evaluate the following expressions:

a

\dfrac{a b c}{a}

b

a^{ 2 b} + c

c

\dfrac{a}{b} + \dfrac{c}{a}

11

If a = 0.4, b = - 2.5 and c = 5, evaluate the following expressions:

a

\dfrac{a b}{c}

b

\left( a b\right)^{2} - c

c

a + b c - a

Substitution into formulas
12

The perimeter of a triangle is defined by the formula P = p + q + r.

Find P if the length of each of its three sides are:

a
p = 17\text{ cm}, q = 16\text{ cm} and r = 14\text{ cm}
b
p = 6\text{ cm}, q = 3\text{ cm} and r = 7\text{ cm}
13

The perimeter of a square with side lengths of a is given by the formula P = 4a.

Find P if the length of each side is 7\text{ cm}.

14

The area of a rectangle is given by the formula A=\text{ Length }\times \text{ Width}. If the length of a rectangle is 2\text{ cm} and its width is 3\text{ cm}, find its area.

15

The perimeter of a rectangle is given by the formula P = 2 \times \left(l + w\right) , where l is the length and w is the width. If the width of a rectangle is 10\text{ cm} and its length is 5\text{ cm}, find its perimeter.

16

The area of a triangle is given by the formula A = \dfrac{1}{2} \times \text{base} \times\text{height}. If the base of a triangle is 5\text{ cm} and its height is 8\text{ cm}, find its area.

17

The area of a rhombus is given by the formula A = \dfrac{1}{2} x y, where x and y are the lengths of the diagonals. If the diagonals of a rhombus have lengths of 2\text{ cm} and 4\text{ cm}, find the area of the rhombus.

18

The area of a square with side lengths of s is given by the formula A = s^{2}. Find A if the length of each side is 6\text{ cm}.

19

The equation of a straight line is given by the formula y = m x + c. Given that m = 6, x = - 4 and c = 9, find the value of y.

20

For many 3 dimensional shapes, we can find the number of edges, E, on the shape by using the formula: E = V + F - 2 where V is the number of vertices and F is the number of faces.

Find the number of edges of a 3 dimensional shape which has:

a

7 vertices and 7 faces

b

8 vertices and 6 faces

21

The surface area of a rectangular prism is given by formula S = 2 \left( l w + w h + l h\right), where l , w and h are the dimensions of the prism. Given that a rectangular prism has a length of 8\text{ cm,} a width of 7 \text{ cm} and a height of 9\text{ cm}, find its surface area.

22

The volume of a rectangular prism is given by the formula V = l \times w \times h, where l , w and h are the dimensions of the prism. Given that a rectangular prism has a length of 4\text{ cm}, a width of 8\text{ cm} and a height of 5\text{ cm}, find its volume.

23

The simple interest generated by an investment is given by the formula I = \dfrac{P \times R \times T}{100}.

Given that P = 1200, R = 5 and T = 9, find the interest generated.

24

Converting a measure of temperature from Celsius to Fahrenheit is given by the formula F = 32 + \dfrac{9 C}{5}

Given that C = 15, evaluate F.

25

Converting a measure of temperature from Fahrenheit to Celsius is given by the formulaC = \dfrac{5}{9} \left(F - 32\right)

a

Given that F = 50, evaluate C.

b

The temperature inside a freezer is 86 \degree\text{F}. Convert this temperature into Celsius.

26

In physics, Newton's second law states that F = m a, where F is the force of on object (measured in Newtons), m is the mass of the object (in kilograms) and a is the acceleration of that object (measured in metres/second^{2}).

Calculate the force, F, created from an object with:

a
A mass of 6 kilograms and an acceleration of 13\text{ m}/\text{s}^{2}.
b
A mass of 1540 grams and an acceleration of 19\text{ m}/\text{s}^{2}.
27

Newton's second law of motion states that a = \dfrac{F}{m}, where F is the force acting on an object (in Newtons), m is the mass of the object (in kilograms) and a is the acceleration of that object (in \text{m}/\text{s}^{2}). Calculate the acceleration of an object with a mass of 25 kilograms and a force of 775 Newtons acting on it.

28

The volume of a sphere can be calculated using the formula V = \dfrac{4}{3} \pi r^{3}, where r is the radius of the sphere. Given that a sphere has a radius of 2\text{ cm}, calculate its volume correct to two decimal places.

29

The value of a variable T is defined by the formula T = a + \left(n - 1\right) d. Given that a = 6, \\ n = 5 and d = 8, find the value of T.

30

Sally bought a television series online. The television series was 7.2 gigabytes large and took 2 hours to download. The formula b = 8 B converts gigabytes, B, to gigabits b. Find the size of the television series in gigabits.

31

The sum of n terms in an arithmetic sequence is defined by the formula \\ S = \dfrac{n}{2} \left( 2 a + \left(n - 1\right) d\right). Given that n = 10, a = 3 and d = 9, find the value of S.

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Outcomes

2.2.1.1

substitute numerical values into linear algebraic and simple non-linear algebraic expressions, and evaluate, e.g. order two polynomials, proportional, inversely proportional

2.2.1.2

find the value of the subject of the formula, given the values of the other pronumerals in the formula

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