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2. Equations, Formulae & IdentitiesEdexcel IGCSE Maths: Topic test

20 questions, 52 marks

Edexcel IGCSE Maths

2. Equations, Formulae & Identities topic test

Total 52 marks

Name

Class

Date

  1. 1
    A maths tutor sets a starter exercise using the expression P=4x2−3xP=4x^2-3x and the index expression 2a3×3a22a^3\times3a^2, to check substitution and index-law skills before a test.
    (a)
    What is the value of P=4x2−3xP=4x^2-3x when x=−2x=-2?
    [1 mark]
    • A22
    • B10
    • C−22-22
    • D14
    (b)
    Simplify 2a3×3a22a^3\times3a^2.
    [1 mark]
    • A6a66a^6
    • B5a55a^5
    • C6a56a^5
    • D6a−16a^{-1}
    (c)
    Evaluate (3a2)0(3a^2)^0, for a≠0a\neq0.
    [1 mark]
    • A0
    • B1
    • C3
    • D9

    Total for question 1: 3 marks

  2. 2
    A bicycle hire company charges a fixed deposit plus an hourly rate. For one hire lasting xx hours, the total cost in dollars satisfies 4x+9=454x+9=45. A separate car park charge, in dollars, for yy half-hour blocks satisfies 7(y−4)=3y+207(y-4)=3y+20.
    (a)
    Solve 4x+9=454x+9=45 for xx.
    [2 marks]
    (b)
    Solve 7(y−4)=3y+207(y-4)=3y+20 for yy.
    [2 marks]

    Total for question 2: 4 marks

  3. 3
    A café sells two sizes of smoothie, small (ss dollars) and large (ll dollars). One order of 2 small and 3 large smoothies costs $23.50 total, giving 2s+3l=23.52s+3l=23.5. Another order of 4 small and 1 large smoothie costs $18.50 total, giving 4s+l=18.54s+l=18.5.
    (a)
    Solve the simultaneous equations to find ss, the price of a small smoothie in dollars.
    [3 marks]
    (b)
    Hence find ll, the price of a large smoothie, and verify your solution satisfies 2s+3l=23.52s+3l=23.5.
    [3 marks]

    Total for question 3: 6 marks

  4. 4
    A rectangular vegetable plot has length (x+7)(x+7) metres and width xx metres. The area of the plot is 60 square metres.
    (a)
    Form an equation in xx for the area of the plot, and show that it can be written as x2+7x−60=0x^2+7x-60=0.
    [4 marks]
    (b)
    Solve x2+7x−60=0x^2+7x-60=0 by factorisation to find the width of the plot, xx (a positive value).
    [4 marks]
    (c)
    The farmer increases the width by 20% but keeps the length the same. Calculate the percentage increase in the area of the plot.
    [5 marks]

    Total for question 4: 13 marks

  5. 5
    A tutor sets three quick-fire algebra questions on expanding and factorising, based on the expressions (x+8)(x−5)(x+8)(x-5), 8xy+12y28xy+12y^2 and 6x2−5x−66x^2-5x-6.
    (a)
    Expand and simplify (x+8)(x−5)(x+8)(x-5).
    [1 mark]
    • Ax2−3x−40x^2-3x-40
    • Bx2+3x−13x^2+3x-13
    • Cx2+3x+40x^2+3x+40
    • Dx2+3x−40x^2+3x-40
    (b)
    Factorise fully 8xy+12y28xy+12y^2.
    [1 mark]
    • A4y(2x+3y)4y(2x+3y)
    • B4(2xy+3y2)4(2xy+3y^2)
    • C2y(4x+6y)2y(4x+6y)
    • D4y(2x+3y2)4y(2x+3y^2)
    (c)
    Factorise 6x2−5x−66x^2-5x-6.
    [1 mark]
    • A(2x+3)(3x−2)(2x+3)(3x-2)
    • B(2x+2)(3x−3)(2x+2)(3x-3)
    • C(2x−3)(3x+2)(2x-3)(3x+2)
    • D(x−3)(6x+2)(x-3)(6x+2)

    Total for question 5: 3 marks

  6. 6
    A cylindrical water tank has total surface area S=2πr2+2πrhS=2\pi r^2+2\pi rh. A pendulum's period is given by T=2πlgT=2\pi\sqrt{\frac{l}{g}}.
    (a)
    Rearrange the formula S=2πr2+2πrhS=2\pi r^2+2\pi rh to make hh the subject.
    [2 marks]
    (b)
    Rearrange the formula T=2πlgT=2\pi\sqrt{\frac{l}{g}} to make ll the subject.
    [2 marks]

    Total for question 6: 4 marks

  7. 7
    A teacher sets a proof task using nn to represent any integer.
    (a)
    Prove that the sum of any two consecutive odd numbers is always a multiple of 4.
    [3 marks]
    (b)
    Prove that (n+3)2−(n−3)2(n+3)^2-(n-3)^2 is always a multiple of 12 for any integer nn.
    [3 marks]

    Total for question 7: 6 marks

  8. 8
    The temperature, in degrees Celsius, inside a greenhouse over a 10-hour period is modelled by C(t)=−t2+8t+5C(t)=-t^2+8t+5, where tt is the number of hours after sunrise.
    (a)
    Write C(t)=−t2+8t+5C(t)=-t^2+8t+5 in the form a(t+b)2+ca(t+b)^2+c.
    [4 marks]
    (b)
    Hence write down the maximum temperature in the greenhouse during this period, and the number of hours after sunrise at which it occurs.
    [4 marks]
    (c)
    Using your completed-square form, find the values of tt for which the greenhouse temperature is at least 16°C.
    [5 marks]

    Total for question 8: 13 marks

End of questions