Question 64465
83. 3A^2+3AB-B^2 
Comment: I think you typed this wrong.
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85. 2Y^2+5Y+6Y+15
=Y(2Y+5)+3(2Y=5)
=(2Y+5)(Y+3)
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87. 2X^2-3XY -2XY+3Y^2
=2x(x-y)-3y(x-y)
=(x-y)(2x-3y)
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89. M^4+4M^3+4M^2+2M+4 
=(m^4+4m^2+4)+(4m^3+2m)
=(m^2+2)^2+2m(2m^2+1)
You may have typed this one wrong also.
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Cheers,
Stan H.