Question

Which of the following is equivalent to the radical expression below when X>7? √x-7•√x+1 OA. √x²+8x-7 OB. √x²-6x+7 OC. square root x^2+8x+7OD. square root x²-6x-7

Answer 1

Given:

The given radical expression is,

`√(x-7)\cdot√(x+1)`

Required:

To find the expression equivalent to the given radical expression when

`x>7`

Step-by-step explanation:

Let us solve the given expression.

`\begin{gathered} √(x-7)\cdot√(x+1) \\ =√((x-7)\cdot(x+1)) \\ =√(x^2+x-7x-7) \\ =√(x^2-6x-7) \end{gathered}`

Final Answer:

The expression equivalent to the given radical expression when

`x>7`

is given by,

`√(x^2-6x-7)`

Option D is correct.