Question 117515
6y/(y^2+5y+4)+4y/(y^2-1)
=6y/((y+4)(y+1))+4y/((y+1)(y-1)) Factor the denominators.
=(6y(y-1)+4y(y+4))/((y+4)(y+1)(y-1)) LCD is the denominator
=6y^2-6y+4y^2+16y/((y+4)(y+1)(y-1)) Expand the numerator.
=10y^2+10y/((y+4)(y+1)(y-1)) Combine terms.
={{{10y*cross(y+1)/((y+4)cross(y+1)(y-1))}}}
=10y/((y+4)(y-1)) Voila!
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Ed