Roots and Exponents doubt from video

[user4458]

Here, if we assume: a = root 2 ; b = - root 2
if we add a + b it will result into a 0, jus the opposite of what was explained to us in example 2 of (module 3, part 1 quiz question 2)

Pls explain the difference between both the questions as this has got us confused!

[cylverixxx]

a = \sqrt{2} doesn’t conform to the “a is a rational number” part

[user4458]

Ah got it! my bad, i missed on that concept.

in the above question, how to calculate cube root of -1/2? what’s the logical way of thinking for this?

[cylverixxx]

You can start by cubing both sides instead