What belongs in the box marked with the question mark in the proof?Given: 3x - 4 = 2(x + 8), Prove: x = 20
@SmoothMath can you help?
Would it be The Distributive Property?
adding 4 on both sides
This is a Two-Column proof, the reasons have to be postulate, theorems, properties, etc.
@zepp I've heard you're good with two column proofs
We've send 2x to the left side, I believe it should be Associative Property of Addition 3x = 2x + 20 3x + 0 = 2x + 20
Zepp, the question mark is in the column after the statement 3x = 2x + 20 so it needs to be a reason for going from 3x-4 = 2x + 20 to 3x = 2x+20 You should ask yourself how it is that we're able to get from one to the other, and the answer, as rabhajishek point out, is that we added 4 to both sides. So that's what we DID, but what is it that ALLOWS us to do that? The associative property of addition isn't it, I wouldn't say. That's the one that would allow us to rewrite (a+b)+c as a+(b+c) Instead, there's a property that lets us add something to both sides of an equation without unbalancing it. What's that property called? The addition property of equality.
Sorry for the long response time, Feara. I was nappin' :3
Oh I see :D
Thanks for the clarification @SmoothMath
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