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x²+y²=25, y-2x= 5 y = 5+2x  -----> y² = (5+2x)² = 25 + 20x +4x² x² + 4x² + 20x + 25 = 25 5x² + 20 x = 0 x = 0 y =...

a) (x+7)(x-7) b) y = (x^2) - 49 y' = 2x 0 = 2x x = 0 y = (0^2) - 49 y = -49, x = 0

The key here is to simplify the left hand side. There are two different approaches to take here, one slightly faster but both perfectly legitimate. First approach: Remember the formula (a + b)^{2} = a^{2}...

Simple interest means the amount of money increases by the same amount each year, compound interest means the amount of money increases by the same proportion each year. For example if you deposited £100 ...

1 portion of orange cordial is mixed with 9 portions of lemonade

There are 10 portions in total 

one-tenth of the total volume would be the volume of orange cordial needed 

(1/10) * 1...