Adding and subtracting square roots?

Question

haha i'm feeling kinda dumb at the moment, i'm doing Algebra 1 review, and after being away from algebra for two years i've forgotten alot! now that i'm in Algebra 2, 9th grade, my homework is to complete some algebra 1 stuff, and i cannot for the life of me, remember how to add and subtract non-perfect square roots! Come to think of it, i cant even remember how to multiply a whole number by a square root D:

my homework problems, that i would love help on are:

A:

(square root of) 80 + (square root of) 45 - (square root of) 20

also written as:

√80+√45-√20

and

B:

((1/2)x(square root of 2))x((square root of 6) + (1/2)x(square root of 2))

also written as:

1/2√2(√6+1/2√2)

help will be loved :D

and thanks ahead of time :)

Answer 1

take away the square roots add and subtract them then when ur done put the square root symbol back