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So there are 15 marbles in total (5 + 7 + 3) The probability of the first marble will be the number of blue marbles / total number of marblesTherefore, you do 5/15 = 1/3 Then for the second marble you do ...

First of all you need to spot a way we can add or subtract these two equations together so that we can get rid of one of the terms. This is easily spotted by writing the equations like so:2x - y ...

To factorise an expression of the formax²+bx+c We use the formulaX=(-b+/- (b^2-4ac)^(1/2))/2aExample:Factorise 3X²+2X+-1So here a=3 b=2 c=-1From the formula we get X=1/3 and X=-1And ...

We can take logs of both sides straight away, and using the log rule that alogb = log(b^a)So(4x-1) log(2) = (5 - 2x) log(3)We can expand the bracketsso (4x)log(2) - log(2) = 5log(3) - 2xlog(3)We can group...

Firstly we have an equation y=4x-6. We are given that x=3 and we want to find y. What we must do is substitute x=3 into the equation to get y: y=4(3)-6 =6