Solve: x^4-13x^2+36=0

A. -3,-2,2,3
B.-9,-4,4,9
C.2,3,2i,3i
D.-2,-3,2i,3i

Question

Solve: x^4-13x^2+36=0

A. -3,-2,2,3
B.-9,-4,4,9
C.2,3,2i,3i
D.-2,-3,2i,3i

anonymous · Answer

last question tonight I swear! =D

lgbasallote · Answer

it seems like a case of quadratics...let a = x^2 so a^2 = x^4

a^2 - 13a + 36

does that make it easier?

anonymous · Answer

Oh yeah, I remember now! Thank you so much!

lgbasallote · Answer

dont forget to sub back to x^2 when you're done

anonymous · Answer

first you have to factor x^4-13x^2+36 into two brackets...
so first off, you want to draw your two brackets...(     )(    ) ...then it is just trial and error to get the right order of the terms inside the brackets to get you the original equation...

now, your equation starts off with an x^4, not x^2, so you have to be careful of what you put in each bracket first