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How can I solve reverse percentage questions?

A bag in a sale is reduced by 20%. It now costs £40. What was the original price? Solution 1: Using ratios and basic percentagesA good way to solve this problem is by thinking about what percentage is left a...
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Answered by Madeleine B. • Maths tutor
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Expand (2x-1)(x+3)

Method 1: Foil method (each term of the first bracket are multiplied by each term of the second bracket, and hence the product have 4 terms before simplifying)(2x-1)(x+3) = 2x x + 2x 3 - 1 x -1 3 =2x 2 + 6x ...
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Answered by Cherish N. • Maths tutor
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Find dy/dx in terms of t for the curve defined by the parametric equations: x = (t-1)^3, y = 3t - 8/t^2, where t≠0

The first step is to recognise that, by the chain rule, dy/dx = dy/dt * dt/dx. dy/dt and dt/dx can both be found by differentiating the functions given in the question, to give dy/dt and dx/dt. dt/dx is the ...
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Answered by Alex C. • Maths tutor
21848 Views

How do I solve a simultaneous equation?

Simultaneous equations are a set of equations that have multiple common unknown variables such as two equations which both contain the unknowns x and y. To solve a simultaneous equation the trick is to chang...
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Answered by Lewis K. • Maths tutor
3799 Views

integrate the following: 2x^4 - 4/sqrt(x) +3 with respect to x

The 3 terms of this equation can be integrated separately. The general integration of x n is (x n+1 )/n+1 where n is a real number not equal to -1. This can be applied to the terms 2x 4 , -4/sqrt(x) and 3 se...
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Answered by Adrien F. • Maths tutor
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