Posted by **Katie** on Wednesday, October 7, 2009 at 5:22pm.

4x^4-18x^2=0. I have to find out what x equals by factoring. What I did was

Factor 2x^2(2x^2+-9)=0 then 2x^2(2x+3)(x+-3), resulting in -1.5 and three. But these answers are wrong according to my book. Can you show me step by step how to do this correctly? It would be a huge help!

- Algebra -
**bobpursley**, Wednesday, October 7, 2009 at 6:07pm
They are wrong.

2x^2(2x^2-9)=0

2x^2(xsqrt2-3)(xsqrt2+3)=0

so the roots are 0,0,3/sqrt2, -3/sqrt2)

- Algebra -
**Katie**, Wednesday, October 7, 2009 at 6:35pm
Why did you square root the second line? Would you please be able to explain? Thanks!

## Answer this Question

## Related Questions

- basic Integration - I have three questions which I apparently have 'wrong' ...
- Algebra Zero Product Rule - I'm working with the zero product rule and I've ...
- algebra - how can factoring of 9x^2+18x+8 help factor 9a^2+18ab+8b^2
- Algebra II - I cannot figure out how to work this one. I have tried working it ...
- algebra - 3ax^2 - 27a You can factor that into 3a (x^2 - 9), which also equals ...
- Algebra - How do I factor out the greatest common monomial factor? 1) 9m^7 - 3m^...
- FACTORING - I can't figure out how to factor this. I know you use the technique ...
- Algebra - How does 3x(4x+5)-5(4x+5) factor out to be (4x+5)(3x-5) ? This may be ...
- Algebra: factoring - I need to find the value of x. 9x^3 + 9x = 30x^2 It's ...
- Algebra - 3 (in the nook) of the radical of 8 raised to the second power ...

More Related Questions