Question

15 / √31 - 4

can someone just solve this for me please
PLEASE ANSWER ONLY IF YOU ARE SURE else I am out of the class

Answer 1

`(15)/( √(31) - 4)} = √(31) + 4`

Explanation:

`(15)/(√(31) - 4)\\\\=(15)/(√(31) - 4) * (√(31) + 4)/(√(31)+ 4) \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ [ \ rationalizing \ the \ denominator \ ]\\\\=(15( √(31) + 4 ))/((√(31))^2 - (4)^2) \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ [ \ (a-b)(a+b) = a^2 - b^2 \ ]\\\\=(15 ( √(31) + 4))/(31 - 16)\\\\=(15 (√(31) + 4))/(15)\\\\= √(31) + 4`