GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Retired Moderator
Joined: 19 Nov 2020
Posts: 326
Given Kudos: 64
GRE 1: Q160 V152
What is the sum of the roots of the equation ...
[#permalink]
29 Jul 2021, 17:23
29 Jul 2021, 17:23
3
Bookmarks
00:00
Question Stats:
57% (01:05) correct
42% (01:57) wrong based on 19 sessions
Hide Show timer Statistics
What is the sum of the roots of the equation \(5x^2-x=39\) ?
(A) 0
(B) 0.2
(C) 0.5
(D) 0.7
(E) 1
(A) 0
(B) 0.2
(C) 0.5
(D) 0.7
(E) 1
Re: What is the sum of the roots of the equation ...
[#permalink]
29 Jul 2021, 18:23
29 Jul 2021, 18:23
This requires the quadratic formula.
We know it is (-b ± sqrt(b^2 - 4ac)) / 2a, which splits into...
(-b + sqrt(b^2 - 4ac)) / 2a
(-b - sqrt(b^2 - 4ac)) / 2a
AKA the 2 roots!!!
Adding these up we get -2b / 2a.
Here we know b = -1 and a = 5 after we get the formula in the form 5x^2 - x - 39 = 0 (ax^2 + bx + c = 0).
No we plug and chug and we get 1/5 which is .2.
The answer is B! I hope this helps.
We know it is (-b ± sqrt(b^2 - 4ac)) / 2a, which splits into...
(-b + sqrt(b^2 - 4ac)) / 2a
(-b - sqrt(b^2 - 4ac)) / 2a
AKA the 2 roots!!!
Adding these up we get -2b / 2a.
Here we know b = -1 and a = 5 after we get the formula in the form 5x^2 - x - 39 = 0 (ax^2 + bx + c = 0).
No we plug and chug and we get 1/5 which is .2.
The answer is B! I hope this helps.
What is the sum of the roots of the equation ...
[#permalink]
05 Feb 2022, 00:26
05 Feb 2022, 00:26
Sum of the roots of a quadratic equation = -b/a
a = 5
b = -1
(-(-1))/5 = 1/5 = 0.2
Answer B
a = 5
b = -1
(-(-1))/5 = 1/5 = 0.2
Answer B
