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Factorise x^(2)​​​​ - 49

(x + 7)*(x - 7) Notice difference of two squares. Very important to learn square numbers, primes and multiples and be able to notice them.
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Answered by Georgiana I. • Maths tutor
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What effect will increased temperature have on an equilibrium with a forward reaction which is exothermic?

Increased temperature will favour the backward (endothermic reaction.) Any change imposed on the system will be counteracted by a response which reverses the change, i.e. shift the equilibrium in the directi...
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How does one test for halide ions?

Add to the unknown solution dilute nitric acid, then add silver nitrate solution. If Chloride, bromide or iodide ions are present then a white, cream and yellow precipitate will form respectively of silver h...
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Describe one method of producing oxygen gas.

Decomposition of Hydorgen peroxide solution, H 2 O 2 , using Manganese (IV) oxide as a catalyst. Effervescence is observed as the oxygen gas is evolved and the gas can be collected by displacement of water i...
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You are given sets A: {2,4,6,8,10,12} and B: {1,3,5,7,9,11} explain why A∩B = ∅

There are no shared members of either set. Sets A and B are mutually exclusive (odds and evens.) i.e. A intersect B has no members and is empty.
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Answered by Georgiana I. • Maths tutor
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