quick maths question

Bassmansam

Bassmansam

Bassmansam

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Joined
22 Nov 2007
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Can anyone help me with this question as im rubbish at maths.

Expand and simplify

Expand and simplify 3(x + 5) + 2(5x – 6)

I know you have to multiply everything in the first by everything in the second bracket but im not sure what you do with the two numbers outside the brackets?
 
3x + 15 + 10x -12 = 13x + 3

Numbers outside you can think of as A lots of (bx + c) where you have A(bx+c). It is the coefficient.
 
The numbers before the brackets can be seen as 'lots of'

3(x+5) would be 3 lots of (x+5).

The you treat each side separately and add them together as it says.

3(x + 5) + 2(5x – 6)
3x+15+10x-12
13x+3
 
Bassmansam said:
Can anyone help me with this question as im rubbish at maths.

Expand and simplify

Expand and simplify 3(x + 5) + 2(5x – 6)

I know you have to multiply everything in the first by everything in the second bracket but im not sure what you do with the two numbers outside the brackets?
Click to expand...

You are 22 years old and you are finding it difficult:eek:!!
 
3(x + 5) + 2(5x – 6)

As 3 = 3cosec^2 x - 3cot^2 x
3(x+5) = 3xcosec^2 x - 3xcot^2 x + 15cosec^2 x - 15cot^2 x

As 2 = 2sin^2 x + 2cos^2 x
2(5x - 6) = 10xsin^2 x + 10xcos^2 x - 12sin^2 x - 12cos^2x

3(x + 5) + 2(5x – 6)
= 3xcosec^2 x - 3xcot^2 x + 15cosec^2 x - 15cot^2 x + 10x sin^2 x + 10xcos^2 x - 12sin^2 x - 12cos^2 x

Wait no I'm not doing this right.
 
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