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Factorise and solve x^2 – 8x + 15 = 0

This equation is of the form ax 2 + bx + c = 0 (where a = 1, b = -8 and c = 15). To help solve it, find two numbers that add to give the value of b (the 'sum') and also when multiplied together give the same...
AB
Answered by Andrew B. • Maths tutor
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Explain how electricity is conducted through a metal. To gain full marks your answer must include a description of the structure and bonding in a metal.

Metals can be described as a lattice of close-packed positive ions in a sea of delocalised electrons. Because the electrons are delocalised, they can move freely through the metal.
AB
Answered by Andrew B. • Chemistry tutor
15202 Views

Identify the dehydration product or products of a) ethanol, b) button-2-ol

Dehydration is a process in which an alcohol loses a molecule of water and leaves behind an alkene. The OH group is removed along with an H from any adjacent carbon atom. To work out the answer, firstly draw...
AB
Answered by Andrew B. • Chemistry tutor
5752 Views

There are n sweets in a bag, 6 are orange, the rest yellow. Two sweets are taken out individually without replacement. The probability of which is 1/3. show n²-n-90=0

Firstly, you need to consider the type of problem we are dealing with. This is actually just a tree diagram type question. note that the sweets are not replaced. Letting n = number of sweets in the bag. 6 ar...
JR
Answered by Joel R. • Maths tutor
5209 Views

There are n sweets in a bag. Six of the sweets are orange, the rest are yellow. One sweet is removed from the bag without replacement, then another is removed without replacement. Show that n²-n-90=0

Firstly, you need to consider the type of problem we are dealing with. This is actually just a tree diagram type question. note that the sweets are not replaced. Letting n = number of sweets in the bag. 6 ar...
JR
Answered by Joel R. • Maths tutor
5408 Views