Question 30960
5x^2 - 6xy - 8y^2

(Here you must know how we make factors i.e. splitting of the middle term...if you might not know then please contact me again and I will explain to you... )

= 5x^2 - (10-4)xy - 8y^2

= 5x^2 -10xy + 4xy - 8y^2

taking common from first two i.e. 5x^2 -10xy and last two i.e. 4xy - 8y^2
variables...we get 

= 5x(x-2y) + 4y(x-2y)

= (5x + 4y)(x-2y)...........

hope this will help you 

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