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1) X² +2Y²= 182) X - Y = 3
Rearrange 2) in the form X=3-Y then substitute in to 1); (3-y)²+2Y²=18, this is your new equation 39+3Y+3Y+Y²+2Y^...

0.057 x 15 = 0.855 total = 15 + 0.988 = 15.855

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 ...