Answered

Get the answers you need at Westonci.ca, where our expert community is always ready to help with accurate information. Get immediate and reliable solutions to your questions from a community of experienced professionals on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.


1-29
In the equation x² + kx + 54=0, one root is twice the other root. The value(s) of k is (are)
A. -5.2
B. 15.6
C. 22.0
D. ± 5.2
E. ± 15.6

Sagot :

konrad509
[tex]x_1+x_2=-\dfrac{b}{a}=-k\\ x_1x_2=\dfrac{c}{a}=54\\ x_1=2x_2\\\\ 2x_2+x_2=-k\\ 3x_2=-k\\ x_2=-\dfrac{k}{3}\\\\ 2x_2\cdot x_2=54\\ 2x_2^2=54\\ x_2^2=27\\\\ \left(-\dfrac{k}{3}\right)^2=27\\ \dfrac{k^2}{9}=27\\ k^2=243\\ k=\pm\sqrt{243}\\ k\approx\pm15.6 [/tex]
Thanks for using our platform. We aim to provide accurate and up-to-date answers to all your queries. Come back soon. We hope this was helpful. Please come back whenever you need more information or answers to your queries. We're dedicated to helping you find the answers you need at Westonci.ca. Don't hesitate to return for more.