7.) x^2x-12; x+4 (------- ) (8.) 3x^2-x-4; x+1?

Question

use subsition to determine wheather the given linear expression is a factor of the given polynomial?


help me under stand these example___-------------

Answer 1

For the first one the anwer is yes because when you let x=-4, x^2+x-12 equals 0. Similarly, if you let x=-1 in your second example (because x+1=0 when x=-1) then 3x^2-x-4=3+1-4=0: So x+1 is a factor.

Answer 2

you can use synthetic division.

this is number 8:


-1| 3 -1 -4
-3 4
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3 -4 0 since the last term is zero, x+1 is a factor of it. i can probably help you with number 7 if you rewrite it, i think it is written wrong