SOLUTION: Please help me expand and simplify this: (2x+3)^2+3(x+1)^2. I tried expanding it- but failed to do so. I'm not sure of how to solve this problem but know that the answer is: 7x^2+

Click here to see ALL problems on expressions

Question 627699: Please help me expand and simplify this: (2x+3)^2+3(x+1)^2.
I tried expanding it- but failed to do so. I'm not sure of how to solve this problem but know that the answer is: 7x^2+18x+12. When I tried solving it, I got: 5x^2+9x+12. Here are my steps:
Expand and Simplify: (2x+3)^2+3(x+1)^2
1. 2x^2+6x+9+3[x^2+x+1]
For step 1, I multiplied 2x by the power of 2 which i got: 2x^2, then three times 2 which i got 6x and then i multiplied 3 times 3, which i got 9.
2. 2x^2+6x+9+3x^2+3x+3
I then multiplied 3 times x^2 which i got 3x^2, then i multiplied 3 times x, which i got 3x and then i multiplied 3 times 1 which is three.
Lastly, I gathered the like terms and did steps according to the negative and positive terms and as an answer, I got: 5x^2+9x+12.
Found 2 solutions by ewatrrr, solver91311:
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!

Hi,
(2x+3)^2 +3(x+1)^2
1. x^2+x+9 + 3[x^2+x+1]
7x^2 + 18x + 12
Note:
(2x+3)^2 = (2x+3)(2x+3)
F First terms 4x^2
O Outside terms 6x
I Inside terms 6x
L Last terms 9

(x+1)^2 = (x+1)(x+1)
F First terms x^2
O Outside terms x
I Inside terms x
L Last terms 1

Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website!

Your step 1 is incorrect. Write it out in expanded form and then use FOIL. Firsts: times . Outsides: times . Insides: times . Lasts: times

Then

Now add like terms:

John

My calculator said it, I believe it, that settles it