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OpenStudy (anonymous):
Which value of k makes
(2x + 3)(kx – 5) = 2kx^2 – x – 15 true?
A. –3
B. –1
C. 1
D. 3
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OpenStudy (anonymous):
Please anyone help!!! :(
OpenStudy (johnweldon1993):
foil out those parenthesis
jimthompson5910 (jim_thompson5910):
Hint:
(2x + 3)(kx – 5) = 2kx^2 – x – 15
2x(kx – 5) + 3(kx – 5) = 2kx^2 – x – 15
2kx^2 – 10x + 3kx – 15 = 2kx^2 – x – 15
-10x + 3kx – 15 = -x – 15
-10x + 3kx = -x
I'll let you finish.
OpenStudy (anonymous):
I have no idea how to finish it :(
jimthompson5910 (jim_thompson5910):
you want to solve for k, so you need to isolate it
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OpenStudy (johnweldon1993):
well...we see that our x's can combine no?
-10x + 3kx = -x
combine the x's
add 10x to both sides and get
3kx = 9x
now can you solve for k?
OpenStudy (anonymous):
k is equal to three?
OpenStudy (johnweldon1993):
very good :)
OpenStudy (anonymous):
THANK you so much :):):))))
OpenStudy (johnweldon1993):
no problem...do you understand it?
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OpenStudy (anonymous):
After you kind of simplifying it I understand your steps and how you came to finding k, but I wouldn't have a clue how to start if you didn't show how
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