I have not had algebra in a couple years and I can't remember the how to solve
this problem. I know the answer is supposed to be (-11/6), but I don't know how
they got that answer!
2/(y+3)+ 3/(y-4)= 5/(y+6)
2 3 5
——— + ——— = ———
y+3 y-4 y+6
The LCD is (y+3)(y-4)(y+6)
Multiply every term by that over 1
2 (y+3)(y-4)(y+6) 3 (y+3)(y-4)(y+6) 5 (y+3)(y-4)(y+6)
———·——————————————— + ———·——————————————— = ———·———————————————
y+3 1 y-4 1 y+6 1
Now we cancel everything that will cancel:
1 1 1
2 (y+3)(y-4)(y+6) 3 (y+3)(y-4)(y+6) 5 (y+3)(y-4)(y+6)
———·——————————————— + ———·——————————————— = ———·———————————————
y+3 1 y-4 1 y+6 1
1 1 1
2(y-4)(y+6) + 3(y+3)(y+6) = 5(y+3)(y-4)
2(y2+6y-4y-24) + 3(y2+6y+3y+18) = 5(y2-4y+3y-12)
2(y2+2y-24) + 3(y2+9y+18) = 5(y2-y-12)
2y2 + 4y - 48 + 3y2 + 27y + 54 = 5y2 - 5y - 60
5y2 + 31y + 6 = 5y2 - 5y - 60
Subtract 5y2 from both sides
31y + 6 = - 5y - 60
Subtract 6 from both sides
36y = -66
Divide both sides by 36
y = -66/36
Reduce fraction
y = -11/6
Edwin
AnlytcPhil@aol.com