cuban_mind 2 years ago (x/x-3)^2-2(x/x-3)-15=0

• This Question is Open
1. ZeHanz

If you write it in proper math notation:$\left( \frac{ x }{ x-3 } \right)^2-2\left( \frac{ x }{ x-3 } \right)-15=0$you see that it looks like a quadratic equation... So set p=x/(x-3) to get:$p^2-2p-15=0$ Solve for p. Then remember that p=x/(x-3) and solve that for x!

2. cuban_mind

Yeah whenever I do that I get x=5 and x=-3 but I don't know how to go from there

3. ZeHanz

But you get p=5 and p=-3, so you still have to do solve$\frac{ x }{ x-3 }=5$and$\frac{ x }{ x-3 }=-3$I will get you started with these:$\frac{ x }{ x-3 }=\frac{ 5 }{ 1 }$You see two equal fractions. In general this can be dealt with the following way:$\frac{ a }{ b }=\frac{ c }{ d } \Leftrightarrow ad=bc$So do the multiplications and then solve for x.

4. CR-Jennifer

X=9/2 and x= 5/2

5. ZeHanz

Hold on, let me do it myself... ;)

6. ZeHanz

I've found different solutions, I'm afraid...$x \cdot 1=5 \cdot (x-3) \Leftrightarrow x=5x-15 \Leftrightarrow 4x=15$so x=15/4. Maybe you forgot to multiply 5 and -3?

7. ZeHanz

Second one: x*1=-3*(x-3), so x=-3x+9, 4x=9, x=9/4 So I've got 15/4 and 9/4

8. cuban_mind

ok let me see how you did it lol

9. ZeHanz

I just did...!

10. ZeHanz

Do you understand what went wrong?

11. cuban_mind

No, I don't see how you get 5/1

12. cuban_mind

oh wait! I get it nvm!

13. ZeHanz

Welcome!

14. cuban_mind

Thank you so much! I was so lost! lol

15. ZeHanz

Next time, you won't be!