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1. First let coins in pile I equal x. Then we the question tells us II has twice pile A so we can now write this as 2x. Finally, we can write pile III as 6x - reason is that III has three times pile II...

a) The surface area of a 3 dimensional shape is the sum total of the area of each side of the shape. This cuboid is 3x4x2, and so it has 2 sides with area 3x4 = 12, 2 sides with area 4x2 = 8, and 2 sides ...

Factorise fully the following expression: 2a²b + 6ab²
First, find the common terms by treating, 2a²b and 6ab² as separate objects.
We see common term...

Rearrange one of the equations to make y the subject:y = 5 - 2x Substitute y into the other equation: 3x + 5 - 2x = 7 x = 2 y = 5 - (2 x 2) y = 1

When expanding brackets, we need to make sure each of the terms in the first bracket are multiplied by all the terms in the second bracket (and vice versa). To make sure nothing is missed, we can used the...