Find the value of (x + y) (2x-y) - (x + 2Y) (x-2y), where x = 3, y = 4 Such as the title | Math enthusiast | Mathematical art

Find the value of (x + y) (2x-y) - (x + 2Y) (x-2y), where x = 3, y = 4 Such as the title

(x+y)(2x-y)-(x+2y)(x-2y)
=2x^2-y^2+xy-(x^2-4y^2)
=x^2+xy+3y^2
x=3,y=4
=9+12+3*16
=69

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