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1. 2x+y =182) x-y =6(x-y=6) multiply by +22x-2y = 121) 2x+y = 182) 2x-2y=12 -subtract equation 2 from equation 10x-y=6 -Therefore -y=6 so y= -6Put value for y into either of the equation in order to fi...

Though you are required to understand differentiating from first principles for the exam, questions such as this become quite straightforward once you know the trick.
To differentiate all you have to...

The FOIL technique (First, Outside, Inside, Last) is very useful when expanding out brackets. Using this method we have:2x * x = 2x² (First)2...

Sub y=x^2 - 5x + 4 into x+2y=19x+2(x^2 -5x + 4) = 19x + 2x^2 -10x + 8 =192x^2 - 9x -11 = 0 (2x -11)(x+1) = 0x= 5.5x=-1

From this we can see that equation has 2 parts therefore we should look to using the product rule which is used to differiantiate a two functions multiplied together so (fg)'=f'g+fg'. In this question the...