anonymous 4 years ago solve for t : t^6+4t^3=45

1. Akshay_Budhkar

let$t^3=u$ it converts into an easy solving quadratic equation

2. anonymous

start with $t^6+4t^3-45=0$ then factor. if it is not clear how to factor write as $x^2+4x-45=0$ and factor that

3. Akshay_Budhkar

$u^2+4u-45=0$

4. Akshay_Budhkar

Can u do from here?

5. anonymous

can you help still from this point?

6. Akshay_Budhkar

sure$\begin{array} \\u^2+9u-5u-45=0 \\ \therefore u(u+9)-5(u+9)=0 \\ \therefore (u-5)(u+9)=0\\ u=5 or u= -9 \\ \therefore t^3=5 or t^3=-9 \end {array}$

7. anonymous

thank you!!! this helped a lot!

8. Akshay_Budhkar

Yw :D

9. anonymous

wait so is the answer 5 or -9 or is it something else too?