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anonymous
 one year ago
Which of the following is a root of the polynomial shown below?
f(x)=x^34x^211x+30
A. 3
B. 0
C. 1
D. 6
anonymous
 one year ago
Which of the following is a root of the polynomial shown below? f(x)=x^34x^211x+30 A. 3 B. 0 C. 1 D. 6

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UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1\[f(x) = x^34x^211x+30\] so given that polynomial, we need to use the rational root test. So using the last term (that's 30) find all factors of 30 plug in x = one of the factors of 30 and see if your result is 0 If it's 0, then we have a root If it's not 0 we don't have root and if all roots don't work, then the rational root test fails

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1oh... we have multiple choice... that's good. We can use either 3,1, or 6. Hint: 0 doesn't work. Is it C? let's try it let x = 1 \[f(1) = 1^34(1)^211(1)+30\] try computing f(1)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I got 11611+30 = 0 unless I did something wrong

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1something isn't right for the 4(1)^2 part

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1(1)^2 means write 1 twice (1)(1) so for that part 4(1)(1) what's 4 x 1 x 1 ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh oops is it 1411+30=16 so it's not c?

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1not c. so cross that out

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1so it's either 3 or 6

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Oh I got it. I think it's a? 2736+3330=0

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.1\[f(3) = (3)^34(3)^211(3)+30\] \[f(3) = 274(9)+33+30\] \[f(3) = 2736+33+30\] \[f(3) = 63+63\] \[f(3) = 0\] so yes 3 is a root of the polynomial you can just write 0. a negative sign isn't required.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay thanks!! I get it now :)
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