Question

Solve:
35/X^2=4x+15

Answer 1

Multiply the first with x^2 on both sides
You get: 4x^3 +15x^2 = 35

Then make a substitution t = x^2, where t>0 and move over 35

You get: 4t ^ 2 +15 t-35 = 0
There you have a quadratic equation that you can solve, but since t = x^2, you get complex roots ...

Answer 2

What do you mean by substuitute? I get the 4x^3 but how do you make it a quadratic?

Answer 3

By putting something = x ^ 2, you can simplify your calculation, but do not forget to replace your income in your variable at the end...
By example sett t = x^2, you get:
4t^2 +15t-35 = 0
Now solve the equation in the same as if t would be x
When you know what t is, you know what x ^ 2 is because t = x ^ 2

Answer 4

Thank you!