[GMAT math practice question]
What is the product of all roots of the equation √x+1 = x-√x-1?
A. 1
B. 2
C. 3
D. 4
E. 5
What is the product of all roots of the equation √x+1 = x-
This topic has expert replies
- Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
- Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
=>
√x+1 = x-√x-1
=> 2√x = x-2
=> 4x = (x-2)^2, after squaring both sides,
=> 4x = x^2-4x+4
=> x^2-8x+4 = 0
If p and q are roots of a quadratic equation, then the quadratic equation is (x-p)(x-q) = 0 or x^2 -(p+q)x + pq = 0.
The constant term pq is the product of the roots.
Thus, the constant term 4 of the equation x^2-8x+4 = 0 is the product of the roots of the equation √x+1 = x-√x-1.
Therefore, the answer is D.
Answer: D
√x+1 = x-√x-1
=> 2√x = x-2
=> 4x = (x-2)^2, after squaring both sides,
=> 4x = x^2-4x+4
=> x^2-8x+4 = 0
If p and q are roots of a quadratic equation, then the quadratic equation is (x-p)(x-q) = 0 or x^2 -(p+q)x + pq = 0.
The constant term pq is the product of the roots.
Thus, the constant term 4 of the equation x^2-8x+4 = 0 is the product of the roots of the equation √x+1 = x-√x-1.
Therefore, the answer is D.
Answer: D
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]