[24hoursmiles]

Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

[onurdmrkrn]

4x^2 + 12x + 9 + 3( x^2 + 2x + 1 )

4x^2 + 12x + 9 + 3x^2 + 6x+ 3

7x^2 + 18x + 12

[TenOfThem]

(Original post by 24hoursmiles)
Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

Think about the terms that you get

2x * 2x =

2 * 2x * 3 =

3*3 = 9

[24hoursmiles]

(Original post by onurdmrkrn)
4x^2 + 12x + 9 + 3( x^2 + 2x + 1 )

4x^2 + 12x + 9 + 3x^2 + 6x+ 3

7x^2 + 18x + 12

Thanks for replying, would you mind just explaining it a tad..unsure on how you got the first line of you workings?

[TenOfThem]

(Original post by onurdmrkrn)
4x^2 + 12x + 9 + 3( x^2 + 2x + 1 )

4x^2 + 12x + 9 + 3x^2 + 6x+ 3

7x^2 + 18x + 12

The guidance in this forum asks that we do not give full solutions

[TenOfThem]

(Original post by 24hoursmiles)
Thanks for replying, would you mind just explaining it a tad..unsure on how you got the first line of you workings?

Look at post 3

[onurdmrkrn]

(Original post by 24hoursmiles)
Thanks for replying, would you mind just explaining it a tad..unsure on how you got the first line of you workings?

I'm sorry my English is not very good. but the math is great.
If I can help more simple sentences.

[onurdmrkrn]

(a+b)^2 = a^2 + 2.a.b + b^2

[Lord of the Flies]

(Original post by 24hoursmiles)
Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

right?

You omitted a few terms, hence the wrong result.

[steve2005]

(Original post by 24hoursmiles)
Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

Why is your title "Factorisation" ?

[Dalek1099]

(Original post by 24hoursmiles)
Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

You are going wrong by forgetting that its 2x and not x-this means that you will get double the amount of xs and x^2 and for the 2nd part every term should be timised by 3 not just the x^2.

[Dmon1Unlimited]

(Original post by 24hoursmiles)
Hello
Can someone please tell me where in my working I am going wrong, its driving me mad!

(2x+3)^2 + 3(x+1)^2

I thought it expanded to..
2x^2 + 6x + 9 + 3x^2 + 2x +1 = 5x^2+8x+10..?
yet the answer is .. 7x2 + 18x+ 12

Any advice?

(2x)^2 =(2^2)(x^2) not 2x^2