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Factorise 2x^2+5x - 3

When factorising a quadratic expression the aim is to put the expression into brackets. Step 1: Label each expression as a b c2x2 = a 5x = b -3 = cStep 2: Multiply a with c number 2 * -3 = -6 Step 3: Know yo...
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Answered by Victoria A. • Maths tutor
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Factorise x² + 6x + 8

A quadratic equation is written in the form: ax 2 + bx + cTo factorise, we need to know what 2 numbers multiply to make ac and add to make bac= 8b=64 x 2=8 4+2 = 6We replace b for these two numbers so the eq...
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Answered by Laila M. • Maths tutor
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Describe and explain how the alveoli are adapted to perform efficient gaseous exchange

The alveoli are arranged in clusters at the end of the bronchioles in the lungs. The lungs contain an extremely large surface area of alveoli (around 70m2) which acts to provide the maximum space for the exc...
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Answered by Joe P. • Biology tutor
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What mass of sodium hydroxide would need to be dissolved to make 100 cm^3 of a 0.5 mol dm^-3 solution? (3 marks)

Number of moles = (0.5 x 100)/1000 = 0.05 moles (1 mark)Molar mass, M, of NaOH = 23 + 16 + 1 = 40 (1 mark)Mass of NaOH needed = moles x M = 0.05 x 40 = 2g (1 mark)correct answer alone scores 3 markscorrect f...
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Answered by Aarif A. • Chemistry tutor
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I've heard the word supertonic before. What does this mean?

Each of the seven scale degrees in the major and minor scales has been given a fancy name: TonicSupertonicMediantSubdominantDominantSubmediantLeading tone These names are often used when referring to pitches...
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Answered by Liam G. • Music tutor
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