re: what is the answer to this facebook math problem?

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The pattern is a*b+a = c.


Or a*(b+1) = c

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lolwut

n = 1: 1 + 4 = 5
n = 2: 2 + 5 = 12
n = 3: 3 + 6 = 21
n = 8: 8 + 11 = 96

The pattern is as follows, where the multiplication of the second term by n is implicit in the problem as stated, which is the trick:

n + n(3+n) = x

This is another illustration of what I was talking about earlier, why 96 is the best answer. Its pattern doesn't require making a special case out of the first equation, which you must do to get 40.

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To arrive at the correct answer you have to know the question, where in the information given is it indicated that the answer involves a relationship between the four equations?

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Oh FFS, the answer cannot be potato.

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The problem wasn't asking anything other than, "8 + 11 = ?". Even though other information some false, all irrelevant was provided, any answer other than 19 requires the unwarranted redefinition of standard mathematical symbols.

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That interpretation reduces the "problem" to a joke whose punchline is 19, the joke being that the normally implicit truth of a system in such problems cannot be assumed here. I think that interpretation is belied by the fact there is a simple underlying pattern to it.

40

96

1x4=4+1=5
2x5=10+2=12
3x6=18+3=21
8x11=88+8=96

96

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The pattern is a*b+a = c.


Or a*(b+1) = c

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These equations are equivalent.

The second is the simplified version of the first.

the answer would be 96.

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Why not just say n^2 + 4n = x?

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Because that trivial algebraic manipulation hides the trick they're using that I wanted to expose.