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A washing machine costs £500 in a sale and was reduced by 20%. What was its original price?

Maths is pretty straight forward, you just need to get the key information out the question.So, we have a washing machine that costs £500 on sale. It has been reduced by 20%, so we need to find the original ...
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Answered by Raghavi S. • Maths tutor
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Use calculus to find the set of values of x for which f(x) = x^3 - 9x is an increasing function.

f(x) is an increasing function when its gradient is positive. To find the the gradient of the the function we must differentiate it:d/dx f(x) = 3x 2 - 9. To differentiate we multiply the exponent by the coef...
Answered by • Maths tutor
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3 green balls, 4 blue balls are in a bag. A ball is removed and then replaced 10 times. What is the probability that exactly 3 green balls will be removed?

(Binomial)P(G=3) : ( 10 C 3 )(3/7) 3 (4/7) 7
Answered by • Maths tutor
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Evaluate gf(-5) for the functions f(x)=3x+7, g(x)=3x^2+6x-9

I like to think of gf(-5) as g ( f(-5) ), which helps visualise the order in which you need to calculate the output for each function. First you need to find the answer for f(-5), which you then use as the i...
Answered by • Maths tutor
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Factorise the expression given

2x 2 -2x+4 =2x 2 +2x-4x+4 =2x(x+1)-4(x+1) =(x+1)(2x-4)
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Answered by Rachael H. • Maths tutor
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