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What's the best way to work out any percentage of a given number, e.g. 63% of 450?

The best way to approach this is to begin by working out what 1% of 450 would be: 450 is 100% of 450 So to work out what 1% of 450 is: 450 ÷ 100 = 4.5 Now we know that 1% of 450 is 4.5To work out 63% of 450,...
IW
Answered by Isobel W. • Maths tutor
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Simplify √(4x^8).

√(4x 8 ) = √4 x √(x 8 ) = 2 x (x 8 ) 1/2 = 2x 4 Remember that (x n ) p = x np .
DS
Answered by Della S. • Maths tutor
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Expand and simplify the following expression: x(5x – 2) – 3(x2 – 2x + 7)

5x2 – 2x – 3x2 + 6x – 21= 2x2 + 4x − 21
Answered by • Maths tutor
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The longest side in a right-angled triangle is 12cm. One of the shorter sides is 4 cm. Calculate the perimeter of the triangle

12 2 = 4 2 + x 2 [This is pythagoras' theorem (a 2 = b 2 + c 2 ) ] 144 =16 + x 2 128 = x 2 11.31 = x Perimeter = 11.31 + 12 +4 = 27.31
RC
Answered by Rachel C. • Maths tutor
8262 Views

Which has a lower boiling point chlorine or bromine, and why?

Chlorine has a lower boiling point as it is smaller in size than bromine. Chlorine has fewer electrons than bromine and fewer electron shells so chlorine is smaller in atomic radius. Size affects the strengt...
GF
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