Question

Help me please!!

what is the product of the radical expression?
(7- sqr root 2)(8+ sqr root 2)

a. 13+15 sqr root 2
b. 54- sqr root 2
d. 54+56 sqr root 2

Answer 1

The answer is b. 54- sqr root 2
The expression is:
`(7- √(2) )(8+ √(2) )`
Multiply values with each other:

`(7- √(2) )(8+ √(2) )=7*8+7* √(2)- √(2)*8- √(2)* √(2)= \\ =56+(7 √(2) -8 √(2))- (√(2)) ^(2) =56- √(2) -2=56-2- √(2)=54- √(2)`

`54- √(2)` is 54- sqr root 2