Question

Simplify the following:
i) (x-2y)(y-3x)+(x+y)(x-3y)-(y–3x)(4x–5y)
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Answer 1

(x-2y)(y-3x)+(x+y)(x-3y)-(y-3x)(4x-5y)

x( y-3x)-2y(y-3x)+x(x-3y)+y(x-3y)-y(4x-5y)+3x(4x-5y)

xy-3x²-2y²+6xy+x²-3xy+xy-3y²-4xy+5y²+12x²-15xy

xy+6xy-3xy+xy-4xy-15xy-3x²+x²+12x²-2y²-3y²+5y²

7xy-2xy-19xy-2x²+12x²-5y²+5y²

7xy-21xy+10x²

-14xy+10x²

10x²-14xy