Completing the square question (how to arrange it when a >1)

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Just pull the factor of two out, like this:

$\displaystyle 2x^2 - 8x + 7 \equiv 2(x^2 - 4x) + 7$

then complete the square on the inside bit and multiply out, you'll end up with something of the form $2(x-a)^2 + b$

Edit to add: when I said a,b in my post I mean general numbers a and b, not the coefficients of the quadratic.

just expand

a( x - b )² + c

and compare the relevant sections to find a,b,c

Thanks

Thanks