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Solve these simultaneous equations. 2x + y = 10 and 3x + 4y = 25.

2x + y = 10 (1) 3x + 4y = 25 (2) 1. Eliminate y. Method 1: (1) x 4: 8x + 4y = 40 (1') (1') - (2): 5x = 15 Method 2: Rearrange (1): y = 10 - 2x (1") Substitute (1") into (2): 3x + 4(10 - 2x) = 25 (3...
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Answered by Daisy D. • Maths tutor
11961 Views

When should I use the quadratic formula?

If you're asked to solve a quadratic equation, you could factorise it, or you could use the quadratic formula. The quickest way is to factorise, but sometimes the numbers are too tricky to factorise, (if an ...
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Answered by Sarah M. • Maths tutor
3852 Views

How can I prepare for the French oral exams?

Best way to prepare for an Oral exam: Practise speaking Have as much conversation in French as possible, with friends or a tutor (it doesn’t necessarily need to be on the topics, any conversation in French w...
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Answered by Eleanor F. • French tutor
10186 Views

'ei' or 'ie'?

German spelling can be tricky to get to grips with when you first start learning, but there's a simple trick to remembering whether the word you're writing is 'ei' (e.g. 'bleiben') or 'ie' (e.g. 'spielen'). ...
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Answered by Anita H. • German tutor
3924 Views

When do I use 'sein' and when do I use 'haben' in the past tense?

The rule for this is simple, although can be somewhat confusing when you first start learning German! The rule is: if there's movement from one place to another, use 'sein'. If there's not, use 'haben' . Exa...
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Answered by Anita H. • German tutor
51993 Views