Year 9 Yearlyz Flashcards
How do you factorise an algebraic expression
- Find the HCF of the terms and write it outside the brackets
- divide each term by the HCF and write the answers inside the brackets
- To check that it’s correct expand it.
How to expand the difference of 2 squares
The rule is =
(a+b)(a-b) = a2 - b2
The answer is always a minus
What is commission
Commission is earned by sales people. It is calculated as a percentage of the value of items sold or income made.
How do you find the unknown angle
Shift tan 35 ab/c =
How to Find the surface area of a closed cylinder
2 x Pie x radius2 + 2 x pie x radius x height
How do we find the exterior angle of a triangle
It is equal to the sum of the two interior opposite angles
Triangle interior angle + triangle interior angle = triangle exterior angle
How do you find the net pay
Net pay= gross pay - tax - other deductions
How to expand a perfect square
(A + b)2 = a2 + 2ab + b2
E.g (m + 9)2
= m2 + 81m + 92
The 2 at the end are meant to be squared 2
What is continuous data
This can be any time of data such as 42.36263 degrees celcius
What is the sin
Opposite/hypotenuse
Look at the fat index laws in your photos
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What is the median
The middle score
How to find the percentage profit
Profit/Cost Price X 100%
What is discrete data
Legit just whole numbers
Look at chapter 4 and learn
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What is numerical data
Data that can be counted
Study CHAPTER 7
Do it
How to add or subtract algebraic fractions
To add or subtract factions, convert them (if needed) so that they have the same denominator, then simply add or subtract the numerators.
How to test for a Pythagorean triad
- square all numbers
- plus the first 2 numbers
- if it equals the third one it is a Pythagoras triad
What is categorical data
These can be put into categories such as someone’s hair colour
What is the units of = Kgs to grams Hours to seconds Kilometres to metres Hours to minutes Days to hours Litres to mL
1kg = 1000 g 1h = 3600 s 1km = 1000m 1hr = 60 min 1d = 24 hrs 1L = 1000mL
How many minutes is 1 degree
1 degree = 60’
How to find the surface area
Find the area of each face and add the areas together
Make sure to square the answer at the end
How to factorise a quadratic trinomial E.g x2 + 6x + 8
E.g x2 + 6x + 8
=(x+__)(x+__)
=(x+2)(x+4)
This is because 2 + 4 is 6 and 2 x 4 is 8
You can find this by dividing 8 by 2,3,4 and then plusing the 2 to whatever you got or 3 to whatever you got.
How to find the area of a trapezium
Area= 1/2 x (side+side) x height
What is the mode
It is the score that occurs most
Power of a power? How to do
When raising a power to another power, multiply the powers together
Negative indices? How to do
A number raised to a negative power gives a fraction with a numerator of 1 then remove the - on the power
How do you multiply algebraic fractions
To multiply fractions, cancel any common fractions and then multiply the numerator and denominator separately e.g
=4/k x 3k/16
=3/4
This is because 4 16 4 times and k goes into k once
How do we write scientific notation
Numbers written in scientific notation are expressed in the form m x 10n
Where m is a number between 1 and 10 and n is an integer
YOU CAN ALSO DO IT ON THE CALCULATOR
How much is GST
10% of the original price
After a discount, how to find the original price
E.g If a tv costs $865 after a 24% discount what was the OG price? =865/76 = 1% = X 100 = $1138.157
What is piecework
Piecework is earned according to the number of items made or tasks completed. Fruit pickers and dress makers earn money this way.
How to factorise a quadratic expression such as 3a2
the 2 is a squared 2
=3(a2-9)
=3(a+3)(a-3)
How to do it=
*look for any common factors and factorise first
*If there are 2 terms try factorising using the difference of 2 squares
*if there are 3 terms try factorising as a quadratic trionomial
*if there are 4 terms try factorising by grouping in pairs
What is the mean
Number of scores
The - is a fraction
What is tan
Opposite/adjacent
How do you find the distance between points of an interval
You create a triangle on the graph and perform Pythagoras theorem to find the distance (hypotenuse)
How do you expand a binomial product E.g ( x + 5)( x + 9)
E.g ( x + 5)( x + 9)
=x (x + 9) + 5(x + 9)
=x2 + 9x + 5x + 45
=x2 + 14x +45
x2 = the 2 is meant to be a high little 2 like a squared 2
How many ‘ are in a “
1’ = 60”
How to factorise the difference of two squares
a2-b2 = (a+b)(a-b)
How to find the area for a rhombus and a kite
1/2 x X x Y
How do you find the hypotenuse
You plus the other sides together
What to do when the power is a fraction
And number raised to the power of 1/2 is the square root of that number and any number raised to the power of 1/3 is the cube root of that number
STUDY 1-04 in book
STUDY 1-06 in book
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How to find the area of a parallelogram
Area x base x height
How do you turn a recurring decimal into a fraction
Type the recurring decimal on your calculator but make sure the recurring number is a LOT OF THEM
Wat is the cos
Adjacent/hypotenuse
Do all exercise 11
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How do you divide Algebraic fractions
To divide a fraction a/b, multiply by its reciprocal b/a
How to find the area of a circle
Pie x (radius)2
The 2 is a squared 2
How do you find the other sides of a triangle using the hypotenuse
- unsquare the sides with numbers accordingly
- hypotenuse - the numbered side
- square the answer
- that is what the other side would be
What is the range
Highest score - lowest score
What is annual leave loading
Annual leave loading is extra pay given during holidays. It is paid at the rate of 17.5% of four weeks of normal pay.
