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(2x+3) (2x+1) = 4x^2 + 8x + 3

(2x-8) (x-4) = 2x^2 - 16x - 32

(4x^2+8x+3) - (2x^2-16x-32) = 1

2x^2 - 8x - 29 = 1

2x^2 - 8x - 30 = 0

x^2 - 4x - 15 = 0

Using the qua...

This is a simple yet standard GCSE question, especially in non-calculator papers. The solution is simple: if the student is picked at random, then the probability 2/5 must represent a ratio where the othe...

Firstly we need to work out the new price of the 3 litres of shampoo after 15% has been taken off.  Let's use the three step method for percentages. 100% is £12.80 £12.80/ 100= £0.128     1% is £0.128 £0....

f'(x)=2x+5

note that f'(x)=nx^n-1

so 2x is originally x² as this is 2x^2-1

and 5 is originally 5x^1-1

 f(x)= x²+5x+c...