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In an arithmetic sequence, the first term is 2, and the fourth term is 14. a) Find the common difference, d. b) Calculate the sum of the first 14 terms, S14.

a) We have that a 1 = 2 and a 4 = 14, so the first thing that we can conclude is that the common difference, d, is positive, and that a 2 and a 3 are in between 2 and 14. We know that a 1 + 3d = 14. Substitu...
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Answered by Zhihong Z. • Maths tutor
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Solve the simultaneous equations 2x - 3y = 7 and 3x + 4y = 2. Do not use trail and improvement.

[ 2x - 3y = 7 ] *3 = [ 6x - 9y = 21 ] [ 3x + 4y = 2 ] *2 = [ 6x + 8y = 4 ] [ 6x + 8y = 4 ] - [ 6x - 9y = 21 ] = [ 17y = -17 ] Therefore, y = -1. Substituting y = -1 into the original equations and solving fo...
EH
Answered by Elizabeth H. • Maths tutor
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A geometric progression has first term 3 and second term -6. State the value of the common ratio.

3/-6 = -2
EH
Answered by Elizabeth H. • Maths tutor
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State one property that all EM waves have in common.

All EM waves travel at the same speed in a vacuum.
EH
Answered by Elizabeth H. • Physics tutor
3039 Views

Explain what is meant by the term "plastic deformation".

Plastic deformation happens to a material when that material is stretched beyond its elastic limit and hence won't return to its original shape. Therefore the material is permenantly mis-shaped.
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Answered by Elizabeth H. • Physics tutor
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