help with a couple of problems

[dan007]

3 (x^2 + 10x +25) -4 (x+5)

now I factored the first into: 3 (x+5)^2 - 4 (x+5)

but what can I do next? just multiply each with each other??


and...


1-8x^2-9x^4

I did the obvious and arranged it into -9x^4-8x^2+1
but what can I do next??

maybe: (3x^2- ) (3x^2+ )

but what numbers would I use there? and the 3x^2 have to be negative right??

 

[pka]

3 (x^2 + 10x +25) -4 (x+5)

now I factored the first into: 3 (x+5)^2 - 4 (x+5)

Next Step: \(\displaystyle (x+5)[3(x+5)-4]\)

 

[dan007]

ah, of course! hate missing little things like that

so i guess it ends in x+5 (3x+11)

any help on the other one? seems trickier

 

[pka]

any help on the other one? seems trickier

\(\displaystyle (1-9x^2)(~?~)\)