If x is positive and y is 1 more than the square of x, then what is the value of x in terms of y?
$$A.\ y^2\ -\ 1$$
$$B.\ y^2\ +\ 1$$
$$C.\ \sqrt{y}-\ 1$$
$$D.\ \sqrt{y\ -\ 1}$$
$$E.\ \sqrt{y\ +\ 1}$$
OA D
Source: Princeton Review
If x is positive and y is 1 more than the square of x, then
This topic has expert replies
-
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Hi,
It's a straight forward question.
Given,
x is positive and y = x^2 + 1
y = x^2 +1
x^2 = y-1
x = sqrt(y-1)
So the answer is D.
OR
We can try numbers too.
If x = 1 then y = 2.
When we substitute y = 2 in the answer choices we should get "x" value as 1.
A. y^2 - 1 = 4 - 1 = 3. Eliminate.
B. y^2 + 1 = 4 + 1 = 5. Eliminate.
C. √(y)− 1 = √2 - 1 = not an integer. Eliminate.
D. √(y - 1) = √(2 - 1) = 1. Hold on.
E. √(y + 1) = √(2 + 1) = 3. Eliminate.
So the answer is D.
It's a straight forward question.
Given,
x is positive and y = x^2 + 1
y = x^2 +1
x^2 = y-1
x = sqrt(y-1)
So the answer is D.
OR
We can try numbers too.
If x = 1 then y = 2.
When we substitute y = 2 in the answer choices we should get "x" value as 1.
A. y^2 - 1 = 4 - 1 = 3. Eliminate.
B. y^2 + 1 = 4 + 1 = 5. Eliminate.
C. √(y)− 1 = √2 - 1 = not an integer. Eliminate.
D. √(y - 1) = √(2 - 1) = 1. Hold on.
E. √(y + 1) = √(2 + 1) = 3. Eliminate.
So the answer is D.
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7261
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We can create the equation:BTGmoderatorDC wrote:If x is positive and y is 1 more than the square of x, then what is the value of x in terms of y?
$$A.\ y^2\ -\ 1$$
$$B.\ y^2\ +\ 1$$
$$C.\ \sqrt{y}-\ 1$$
$$D.\ \sqrt{y\ -\ 1}$$
$$E.\ \sqrt{y\ +\ 1}$$
y = 1 + x^2
y - 1 = x^2
√(y - 1) = x
Answer: D
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews