How to solve polynomial multiple choices?

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Can someone please explain to me where I went wrong with question 9 and 10? I picked A and D. Thanks!

1 Answer
Dec 22, 2017

"see explanation"

Explanation:

(9)to(A)

(10)to(B)

(x^2+a)(x-b)(x+c)=0

"equate each factor to zero and solve for x"

x^2+a=0rArrx^2=-a

"this has no real solutions"

x-b=0rArrx=b in RR^+

x+c=0rArrx=-c !inRR^+

rArr"equation has only 1 valid solution "to(B)