2x^{2 }+ xy - 3y^{2}

How do you go about factorising this simply and easily?

I arrived at the correct answer (x - y)(2x + 3y) only after thinking and playing around with it for ages.

It's been a long time since I went over this in class.

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- Feb 10th 2013, 06:48 PMRadeBasic factorising question
2x

^{2 }+ xy - 3y^{2}

How do you go about factorising this simply and easily?

I arrived at the correct answer (x - y)(2x + 3y) only after thinking and playing around with it for ages.

It's been a long time since I went over this in class. - Feb 10th 2013, 06:52 PMshajalalmia2Re: Basic factorising question
thank you, Basic factorising question

its a really heard thank you for your niche discuse. - Feb 10th 2013, 08:43 PMibduttRe: Basic factorising question
Find the product of the coefficients of x^2 and y^2 which in this case is -6. Now find such pair of factors of -6 so that their sum is the coefficient of middle term, in this case 1. -6 = 2 * -3; -6 = -2 * 3 and so on. we observe that the sum of 3 + ( -2 ) is 1 so we split the middle term and re write the expression

2x2 + xy - 3y2= 2x^2 + 3xy-2xy-3y^2 = x(2x +3y) -y(2x+3y) Etc.....