I have a book that teaches the foundations of algebra. I've become stuck on a question: 3a^2 + 2ab + b, when a = 2 and b = 3. The book says the answer is 27. How is that figure derived?

Thanks!

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- Oct 10th 2012, 08:37 AMMathClownBasic Algebra Question
I have a book that teaches the foundations of algebra. I've become stuck on a question: 3a^2 + 2ab + b, when a = 2 and b = 3. The book says the answer is 27. How is that figure derived?

Thanks! - Oct 10th 2012, 08:50 AMalane1994Re: Basic Algebra Question
As an example, I will vary it a little

$\displaystyle 3a^3 + 4ab + 2b$, when $\displaystyle a = 5$ and $\displaystyle b = 7$

All you do is plug the numbers given into the problem and solve.

$\displaystyle 3a^3+4ab+2b$

$\displaystyle 3(5)^3+4(5)(7)+2(7)$

You just solve it from there.

$\displaystyle =529$

Try it on your own problem. - Oct 10th 2012, 10:07 AMSorobanRe: Basic Algebra Question
Hello, MathClown1

Quote:

I have a book that teaches the foundations of algebra.

I've become stuck on a question: .$\displaystyle 3a^2 + 2ab + b$, when $\displaystyle a = 2$ and $\displaystyle b = 3.$

The book says the answer is 27.

How is that figure derived?

It would helpful if you showed your work.

Then we can see how you got your answer (other than 27).

And we can point out your error

- Oct 10th 2012, 08:06 PMMathClownRe: Basic Algebra Question
Solved it, thanks! It was done this way: (3x2x2)+(2x2x3)+(3) = 27

- Oct 11th 2012, 04:46 AMalane1994Re: Basic Algebra Question
Did you get what I said? You just plug the given values into the equation where the given variable is. Rather simple no?