Question: Root in the Denominator

Comment on Root in the Denominator

calculation on 01:27 is not clear. Am adding 2+2-1-3 should give me 0 not -1. please explain how you got the -1 when you simplify. thanks
greenlight-admin's picture

When simplifying expressions, we need to add like terms.
For example, 2x + 2y - y - 3x simplifies to be x - y. We combine the 2x and -3x separately and we must combine 2y and -y separately.
You are combining ALL of the terms.

So, when simplifying 2 + 2√3 - √3 - 3, we must combine the two like terms 2√3 and -√3. We get 1√3.
Then we combine 2 and -3 to get -1
So, altogether, 2 + 2√3 - √3 - 3 = -1 + √3
Does that help?

do you believe we have enough time on the test day to perform such calculations?
greenlight-admin's picture

Yes, you should have enough time . . . as long as it doesn't take you too long to see what steps are required.

Please which module did you teach conjugate roots
greenlight-admin's picture

It's lesson #29 in this module. Here's the link:


What is the difference between 2.5% of 1438 & 1438 of 2.5%?
greenlight-admin's picture

I've never seen a construction similar to "1438 of 2.5%"
I have no idea what that would mean.

I have a feeling you may be thinking of the property that says "x percent of y = y percent of x"
For example, 10% of 50 = 50% of 10, since both quantities evaluates to be 5.
Similarly, we can say that 2.5% of 1438 = 1438% of 2.5
Was that what you were thinking of?

NOTE: In the future, please post your questions in the comment section beneath the related video lesson. In this case, your question would fit nicely under any lesson on "percent" in the Arithmetic module.

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