6....................

Answer:
option (a)
x - √7x / x - 7
Step-by-step explanation:
Given the expression in the question
√x / (√x + √7)
There are 3 steps to follow
Multiply by √x - √7
√x (√x - √7) / (√x + √7)(√x - √7)
√x .√x - √7.√x / (√x + √7)(√x - √7)
a² - b² = (a+b)(a-b)
√x² - √7x / √x² - √7²
x - √7x / x - 7