7x^3-5x^2-63x+45 use the zero x=3 to find all the zeros of the polynomial function

Question

mathteacher1729 · Answer

Do you know how to do polynomial division?

anonymous · Answer

is that synthetic division?

mathteacher1729 · Answer

Yeah, different names, same process.

anonymous · Answer

i know how but there has to be a faster wayy or id be testing like 13 roots

anonymous · Answer

oh now i get it.. thanks emirzoyan

anonymous · Answer

wlecome :)

anonymous · Answer

welcome*

mathteacher1729 · Answer

You're already given one root. So if you divide by (x+3) you'll end up with a quadratic equation. 

Finding the roots of the quadratic should be easy.

anonymous · Answer

oh like divide the whole thing by x+3

mathteacher1729 · Answer

Arrrgh, no no no, not +3, sorry. :( 

If +3 is a ROOT that means (x - 3 ) is a FACTOR. 


(because if x = +3  then (x- +3) = 0

mathteacher1729 · Answer

So divide by (x-3)

anonymous · Answer

ok no worries

anonymous · Answer

okay i got 7x^2+16x-15 but im lost on how to factor it

mathteacher1729 · Answer

Since 7 is the coefficient of x^2 you know that it's going to factor 

(7x     ) * ( x     ) 

can you fill in the rest?

anonymous · Answer

no im having trouble with that