Westonci.ca is your trusted source for accurate answers to all your questions. Join our community and start learning today! Our platform provides a seamless experience for finding reliable answers from a knowledgeable network of professionals. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

(a) Use the fundamental theorem of algebra to determine the number of roots for 2x^2+4x+7
(b) What are the roots of 2x^2+4x+7 ? Show your work.


Sagot :

9514 1404 393

Answer:

  • 2 roots
  • x = -1 +i(√10)/2, x = -1 -i(√10)/2

Step-by-step explanation:

(a) The polynomial is degree 2, so the fundamental theorem of calculus tells you there are 2 roots.

__

(b) We can "complete the square" to find the two roots.

  2x^2 +4x +7 = 2(x^2 +2x) +7 = 2(x^2 +2x +1) +5 = 2(x +1)^2 +5

This is zero when ...

  2(x +1)^2 = -5 . . . . . subtract 5

  x +1 = ±i(√10)/2 . . . divide by 2, take the square root

  x = -1 ±i(√10)/2 . . . subtract 1