Question

are these correct?

Simplify.

1. 3 + sqrt8/ 2 - 2 sqrt8
simplified: - 8 * sqrt2 + 11 / 14

2. 4/ sqrt5 - sqrt3 - 4/ sqrt5 + sqrt3
simplified: 4 sqrt3

Answer 1

the first one looks good, but I can't parse the second.
You really need to use parentheses when typing rational expressions online.

Answer 2

2. (4/ sqrt5 - sqrt3) - (4/ sqrt5 + sqrt3)
simplified: 4 * sqrt3

Answer 3

still not good enough

you probably meant

4/(√5 - √3) - 4/(√5 + √3) , in that case form a common denominator ....
= ( 4(√5 + √3) - 4(√5 - √3) )/( (√5 + √3)(√5 - √3) )
= (4√5 + 4√3 - 4√5 + 4√3)/(5-9)
= 8√3/-4
= -2√3
check my arithmetic

Answer 4

maybe you mean
4/(sqrt5-sqrt 3) - 4/(sqrt5+sqrt3) ???
[4(sqrt 5 +sqrt 3) - 4(sqrt 5 -sqrt 3)]/(5-3)

(4/2) (2 sqrt 3)

4 sqrt 3

Answer 5

Ahhh confusing!!!