Mr. J Gallagher

Algebra - Worksheet

Junior Cert - Ordinary Level

Add and subtract the like terms

Simplify the following expressions

a)16a – 4c + 10b + 6a – 7b + 3c

b)-14x + 11y + 4x – 13y

Evaluating Expressions
Evaluate the following expressions when x = 2, y = -3

a)x2 – 4xy

b)6xy + 3x2y

c)x2 – y2

Multiplying Brackets

Simplify the following expressions

a)4(3x - 4) + 3(-2x + 5)

b)-3(2x – 6y) – 4(x – y)

c)(3x - 4) (-2x + 5)

Simplifying Fractions

Simplify the following expression

a), hence solve

b), hence solve

c), hence solve

Inequalities

Linear – Solve the following inequality and graph your solution on a number line

a)2x – 3 5, x R

b)3x – 1 > 8, x N

c)4x + 3 < 3x + 10, x R

Factorising

Factorise the following expressions

a)x2 + 2x

b)2y2 + 4y

c)4xy – 12x2

d)3x2y – 15xy

e)x2 – 49

f)4x2 – 25

g)36y2 – 16x2

h)ax + ay + bx + by

i)3ax – 2ay + 3bx – 2by

j)4x – 4y + abx – aby

a)Factorise x2 – x – 20
hence solve x2 – x – 20 = 0

b)Factorise x2 + 3x – 10
hence solve x2 + 3x – 10 = 0

c)Factorise x2 + 4x + 3
hence solve x2 + 4x + 3 = 0

Linear Equations

Solve the following equations

a)x + 2 = 0

b)4x + 3 = 15
verify your answer for b)

c)3x – 1 = 2x + 11

d)3(x + 2) = 0

e)4(x – 2) = 3(2x + 4)

f)2(2x + 1) – 3 (x – 1) = 9

Simultaneous Equations

Linear Simultaneous Equations – Solve the following for x & y

a)x – y = 1

2x + y = 11

b)3x + 2y = 5

2x – y = 1

c)2x + 3y = 7

5x + y = 11

d)x + 4y = 3

4x + 3y = -1

Evaluating Functions

If the function f(x) = 5x – 2, find

a)f(-1)

b)f(3)

c)f(x) = 3

If the function f(x) = x2 – 6, find

a)f(-1)

b)f(3)

c)f(x) = 3

Graphing Functions

Graph the following linear functions

a)f: x  2x + 1 in the domain, -3 x 3.

  • Find the value when f(x) = 0
  • Find the value when x = 2.5

b)f: x  3x – 2 in the domain, -2 x 4.
Find the value when f(x) = 0
Find the value when x = 2.5

Graph the following quadratic functions

a)f: x  x2 – 4x – 5 in the domain, -3 x 3.
Find the values when f(x) = 0
Find the value when x = 2.5

b)f: x  2x2+ 4 in the domain, -3 x 3.

Find the values when f(x) = 0
Find the value when x = 2.5

Real Life Examples

  1. Brendan thinks of a number, adds three and the answer is fifteen. Represent this statement as an equation. Solve the equation and check your answer.
  1. Ryan thinks of a number then subtracts five and the answer is ten. Represent this statement as an equation. Solve the equation and then check your answer.
  1. A farmer has a number of cows and he plans to double that number next year, when he will have twenty-four. Represent this statement as an equation. Solve the equation and check your answer.
  1. A new student enters class and the class now has twenty-five students. Represent this statement as an equation. Solve the equation and check your answer.
  1. The temperature increases by eighteen degrees and the temperature is now fifteen degrees. Represent this statement as an equation. Solve the equation and check your answer.
  1. A farmer doubles the amount of cows he has and then buys a further three cows. He now has twenty-nine. Represent this statement as an equation. How many did he originally have?
  1. Emma and her twin brother will have a total age of forty-two in five years time. Represent this statement as an equation. How old are they at the moment?

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