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# Maths gcse urgent help. watch

1. Solve the equation:
6/y^2 + 5/y -4 = 0
I am cross multiplying so I am getting 6y+5y^2 all divided by y^3 = 4
My method seems incorrect and I am not sure why.
2. All you need to do is cross-multiply to get 5y^2 + 6y -24/(y^3-4y^2) = 0
Then times both sides by (y^3-4y^2), to give 5y^2 + 6y -24=0 as anything times 0 is 0.
Then you use the quadratic formula to get x=1.67 and one more solution, which I'll leave you to figure out, rather than give you the entire answer Hope this helps
3. (Original post by Wolfram Alpha)
Solve the equation:
6/y^2 + 5/y -4 = 0
I am cross multiplying so I am getting 6y+5y^2 all divided by y^3 = 4
My method seems incorrect and I am not sure why.
see above
4. (Original post by 1jonam16)
All you need to do is cross-multiply to get 5y^2 + 6y -24/(y^3-4y^2) = 0
Then times both sides by (y^3-4y^2), to give 5y^2 + 6y -24=0 as anything times 0 is 0.
Then you use the quadratic formula to get x=1.67 and one more solution, which I'll leave you to figure out, rather than give you the entire answer Hope this helps
I don't quite understand where the -24/(y^3-4y^2) came from...
5. (Original post by Wolfram Alpha)
I don't quite understand where the -24/(y^3-4y^2) came from...
You need to cross multiply to get 6(y-4) + 5(y^2). This equals 6y -24 + 5y^2. Also as you cross multiplied, you need to multiply the denominators too. So (y^2)*(y-4)= y^3-4y^2. So you end up with 6y -24 + 5y^2 / y^3-4y^2.
6. Aren't the two answers y=-4/3 and y=1/2 ? What do you mean by cross multiplying?

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