Topics
Geometrical Constructions
- Concept of Angle Bisector
- Drawing a Perpendicular to a Line
- The Property of the Angle Bisectors of a Triangle
- Perpendicular Bisectors of the Sides of an Acute-angled Triangle
- Perpendicular Bisectors of the Sides of an Obtuse-angled Triangle
- Construction of Triangles
- Constructing a Triangle When the Length of Its Three Sides Are Known (SSS Criterion)
- Constructing a Triangle When the Lengths of Two Sides and the Measure of the Angle Between Them Are Known. (SAS Criterion)
- Construct a Triangle Given Two Angles and the Included Side
- Construct a Right-angled Triangle Given the Hypotenuse and One Side
- Congruence Among Line Segments
- Congruence of Angles
- Congruence of Circles
Multiplication and Division of Integers
HCF and LCM
Angles and Pairs of Angles
Operations on Rational Numbers
Indices
- Concept of Exponents
- Concept of Square Number
- Concept of Cube Number
- Laws of Exponents
- Multiplying Powers with the Same Base
- Dividing Powers with the Same Base
- Taking Power of a Power
- Multiplying Powers with Different Base and Same Exponents
- Dividing Powers with Different Base and Same Exponents
- Numbers with Exponent Zero, One, Negative Exponents
- Miscellaneous Examples Using the Laws of Exponents
- Crores
- Finding the Square Root of a Perfect Square
Joint Bar Graph
- Concept of Joint Bar Graph
- Interpretation of a Joint Bar Graph
- Drawing a Joint Bar Graph
Algebraic Expressions and Operations on Them
- Terms, Factors and Coefficients of Expression
- Classification of Terms in Algebra
- Algebraic Expressions
- Addition of Algebraic Expressions
- Subtraction of Algebraic Expressions
- Multiplication of Algebraic Expressions
- Multiplying Monomial by Monomials
- Multiplying a Monomial by a Binomial
- Multiplying a Binomial by a Binomial
- Equations in One Variable
Direct Proportion and Inverse Proportion
Banks and Simple Interest
Circle
- Basic Concept of Circle
- Circumference of a Circle
- Relationship Between Circumference and Diameter
- Arc of the Circle
- Central Angle and the Measure of an Arc
Perimeter and Area
Pythagoras’ Theorem
Algebraic Formulae - Expansion of Squares
Statistics
Notes
Factorising a Binomial:
4, x and y are factors of every term in the binomial 4xy + 8xy2
∴ 4xy + 8xy2
= 4(xy + 2xy)2
= 4x (y + 2xy)
= 4xy (1 + 2y)
We can factorize a binomial by identifying the factors common to both terms and writing them outside the brackets in product form.
This is how we factorise 9a2bc + 12abc2
= 3(3a2bc + 4abc2)
= 3abc (3a + 4c)
(a + b)(a - b) = a2 - b2 is a formula we have already learnt.
Hence, we also get the factors a2 - b2 = (a + b) (a - b).
Example
Factorise: a2 - 4b2
a2 - 4b2
= a2 - (2b)2
= (a + 2b)(a - 2b)
Example
Factorise: 3a2 - 27b2
3a2 - 27b2
= 3(a2 - 9b2)
= 3(a + 3b)(a - 3b).
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