x-2y(3x+5)-4xy=x-6xy-10y-4xy=x-10y-10xy
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(3x-2)(4x+5)+2x(x+3y)=12x^2+15x-8x-10+2x^2+6xy=14x^2+7x+6xy-10
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3a-(2a-1)(4b-3)+5=3a-(8ab-6a-4b+3)+5=3a-8ab+6a+4b-3+5=9a+4b-8ab+2
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2x(3x+5)(4y-6)-2(x+3y)=2x(12xy-18x+20y-30)-2x-6y=24x^2y-36x^2+40xy-60x-2x-6y=24x^2y-36x^2+40xy-62x-6y
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-3(5-3a)-(ab-2c)+\frac{1}{4}(a-c)=-15+9a-ab+2c+\frac{1}{4}a-\frac{1}{4}c=9\frac{1}{4}a-ab+1\frac{3}{4}c-15