# Basic Algebra Question

• October 10th 2012, 08:37 AM
MathClown
Basic 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!
• October 10th 2012, 08:50 AM
alane1994
Re: Basic Algebra Question
As an example, I will vary it a little
$3a^3 + 4ab + 2b$, when $a = 5$ and $b = 7$
All you do is plug the numbers given into the problem and solve.
$3a^3+4ab+2b$
$3(5)^3+4(5)(7)+2(7)$
You just solve it from there.
$=529$
Try it on your own problem.
• October 10th 2012, 10:07 AM
Soroban
Re: Basic Algebra Question
Hello, MathClown1

Quote:

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?

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
• October 10th 2012, 08:06 PM
MathClown
Re: Basic Algebra Question
Solved it, thanks! It was done this way: (3x2x2)+(2x2x3)+(3) = 27
• October 11th 2012, 04:46 AM
alane1994
Re: 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?