What is the product of the radical expression?

(7 _sqrt7)(_6 +sqrt7)

a . _49 _ 42 sqrt7
b . _49 + 13 sqrt7
c . _35 _ 42 sqrt7
d . _6 + sqrt7

Respuesta :

(7 _sqrt7)(_6 +sqrt7)= _49 + 13 sqrt7

Answer:

option (b) is correct

The product of [tex](7-\sqrt{7} )[/tex] and [tex](-6+\sqrt{7} )[/tex] is [tex]-49+13\sqrt{7}[/tex]

Step-by-step explanation:

Given radicals [tex](7-\sqrt{7} )[/tex] and [tex](-6+\sqrt{7} )[/tex]

WE have to find the product of two given radicals

Consider [tex]\left(7-\sqrt{7}\:\right)\left(-6+\sqrt{7}\:\right)[/tex]

Using property of algebra,

[tex]\left(a+b\right)\left(c+d\right)=ac+ad+bc+bd[/tex] , We have ,

[tex]=7\left(-6\right)+7\sqrt{7}+\left(-\sqrt{7}\right)\left(-6\right)+\left(-\sqrt{7}\right)\sqrt{7}[/tex]

Simplifying further , we get,

[tex]=-7\cdot \:6+7\sqrt{7}+6\sqrt{7}-\sqrt{7}\sqrt{7}[/tex]

Adding similar terms , we get,

[tex]=-49+13\sqrt{7}[/tex]

Thus, the product of [tex](7-\sqrt{7} )[/tex] and [tex](-6+\sqrt{7} )[/tex] is [tex]-49+13\sqrt{7}[/tex]

Thus, option (b) is correct