Algebraic notation and simplifying expressions

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शिक्षकों के लिए: Algebraic notation and simplifying expressions (KS3 Maths, Algebra) के लिए इस्तेमाल के लिए तैयार लेसन स्लाइड्स, रिवीज़न नोट्स — इन्हें अपने लेसन में इस्तेमाल करें, या टॉपिक को एक इंटरैक्टिव क्लास एक्टिविटी की तरह चलाएं जिसे आपके शिक्षार्थी लाइव गेम की तरह खेलें।

लेसन नोट्स

Algebraic Notation

  • When a letter and a number are written together, they are multiplied: 3y means 3 × y.
  • When two letters are written together, they are multiplied: ab means a × b.
  • A power shows repeated multiplication: a² means a × a, and a³ means a × a × a.
  • Division is written as a fraction: a/b means a ÷ b.
  • The multiplication sign is usually left out in algebra to avoid confusion with the letter x.

Key Words in Algebra

  • A term is a single number, variable, or product of numbers and variables, such as 5, 3x, or 2ab.
  • An expression is a collection of terms combined by + or −, such as 3x + 2y − 5.
  • An equation states that two expressions are equal, such as 3x + 2 = 11.
  • A formula is a rule connecting variables, such as A = l × w (A = area, l = length, w = width).
  • An identity is true for all values of the variables, such as 2(x + 3) = 2x + 6.

Like Terms

  • Like terms are terms that have exactly the same variables raised to the same powers.
  • For example, 5x and 3x are like terms because both contain x to the power 1.
  • The numbers multiplying the variables are called coefficients; in 5x, the coefficient is 5.
  • Unlike terms, such as 2x and 3y, cannot be combined because the variables are different.

Collecting Like Terms

  • To collect like terms, add or subtract their coefficients and keep the common variable part.
  • For example: 5x + 3x = (5 + 3)x = 8x.
  • Similarly, 7y − 2y = (7 − 2)y = 5y.
  • Only like terms can be collected; for example, 4x + 3y cannot be simplified further.
  • Collecting like terms is an important step when solving equations.

Simplifying Products

  • When multiplying terms, multiply the coefficients and multiply the variables.
  • For example: 3a × 4b = (3 × 4) × (a × b) = 12ab.
  • Use index laws: when multiplying powers of the same variable, add the indices, e.g. x² × x³ = x2+3 = x5.
  • The order of multiplication does not matter, so 2 × x × y can be written as 2xy.

Simplifying Quotients

  • When dividing terms, divide the coefficients and divide the variables.
  • For example: 12x ÷ 4 = 3x.
  • Use index laws: when dividing powers of the same variable, subtract the indices, e.g. x5 ÷ x2 = x5−2 = x3.
  • Any variable divided by itself equals 1, e.g. y ÷ y = 1.

Index Laws in Algebra

  • Multiplication law: am × an = am+n.
  • Division law: am ÷ an = am−n.
  • Power of a power law: (am)n = am×n.
  • Zero index law: a0 = 1 (for any non-zero a).
  • These laws work for any variable or number base.

Simplifying Expressions with Brackets

  • To simplify an expression with brackets, first expand the brackets by multiplying each term inside by the number or variable outside.
  • For example: 3(4x²y − 6y) = 12x²y − 18y.
  • After expanding, collect any like terms.
  • For example: 3(4x²y − 6y) + 7x²y − 3y² + 2(8y − 4y² − 4x²y) simplifies to 11x²y − 11y² − 2y.

स्लाइड्स

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प्रैक्टिस सवाल

फ्री प्रीव्यू — 63 में से 8 सवाल। सभी देखने के लिए साइन अप करें।
  1. 1.In algebra, how is the product a × b normally written?

    Easy
    • Aab
    • Ba + b
    • Ca.b
    • Da × b
  2. 2.What does the expression a² mean?

    Easy
    • Aa × a
    • Ba + a
    • C2 × a
    • Da ÷ a
  3. 3.Simplify: 5x + 3x

    Easy
    • A8x
    • B15x
    • C8x²
    • D2x
  4. 4.Simplify: 4a + 3b − 2a + 5b

    Medium
    • A2a + 8b
    • B2a + 2b
    • C6a + 8b
    • D2a − 8b
  5. 5.Which of the following are like terms? (Select all that apply)

    Medium
    • A3x²y
    • B−5x²y
    • C7xy²
    • D2x²y
    • E4y²x
  6. 6.An expression is a mathematical statement that two things are equal.

    Easy

    True or false?

  7. 7.Match each algebraic expression with its simplified form.

    Easy
    • 5x + 3x
    • 7y − 4y
    • 2a × 3b
    • x² × x³
    • 8x
    • 3y
    • 6ab
    • x⁵
  8. 8.Arrange the steps for simplifying 3(4x²y − 6y) + 7x²y − 3y² + 2(8y − 4y² − 4x²y) in the correct order.

    Medium
    • Expand the brackets: 12x²y − 18y + 7x²y − 3y² + 16y − 8y² − 8x²y
    • Group like terms: (12x²y + 7x²y − 8x²y) + (−3y² − 8y²) + (−18y + 16y)
    • Combine coefficients: 11x²y − 11y² − 2y

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