GMAT Roots: If x>0, then 1/(√(2x)+√x)=
Question
If x>0, then 1/(√(2x)+√x)=
- 1/(√(3x))
- 1/(2√(2x))
- 1/(x√2)
- (√2-1)/(√x)
- (1+√2)/(√x)
Topics: roots, simplifications & cancellations
Solution
Step 1
We multiply numerator and denominator by the expression √(2x)-√x to create a difference of squares in the denominator.
1/(√(2x)+√x) × (√(2x)-√x)/(√(2x)-√x)
Step 2
We simplify the denominator by applying the difference of squares formula.
(√(2x)-√x)/(2x-x)
Step 3
We factor out √x from the numerator.
((√2-1)√x)/x
Step 4
We cancel one factor of √x in the numerator and denominator to obtain the final expression.
(√2-1)√x√x√x = (√2-1)/(√x)
Answer
(√2-1)/(√x) (D)
