what is the sqauring expression of 2x + 9?

Question

Squaring expression?

Answer 1

Hello,

 

Sometimes this can get complicated, but as for the expression above you would do the following:

 

2x+9

 

You have to look at it as one term, so it's sometimes helpful to write

 

(2x+9). Then you won't try and square the 2x by itself or the 9 by itself.

 

So the answer would be:

 

(2x+9)^2, or (2x+9)(2x+9)

 

Then take the first 2x and multiply it into the other(2x+9)

 

2x(2x+9)=4x^2+18x

 

Then take the +9 and do the same.

 

+9(2x+9)=18x+81

 

Now take both answers and combine like terms.

 

4x^2+18x+18x+81

 

Since you can only combine the 18x with the 18x, so the final answer.

 

4x^2+36x+81

 

That is the squaring expression for this one.

 

As a more complex example take 4x^2+5x+4.

 

Put the parenthesis around (4x^2+5x+4) then write it again.

 

(4x^2+5x+4)(4x^2+5x+4)

 

Then multiply all terms.

 

4x^2(4x^2+5x+4)=16x^4+20x^3+16x^2

+5x(4x^2+5x+4)=20x^3+25x^2+20x

+4(4x^2+5x+4)=16x^2+20x+16

 

Now combine all your answers like terms.

16x^4+20x^3+16x^2+20x^3+25x^2+20x+16x^2+20x+16

 

That leaves you with this:

 

16x^4+40x^3+57x^2+40x+16

 

Now to square an irrational expression it works differently.

 

Look at this:

 

6x/5

 

(6x/5)(6x/5)

 

Multiplynthe two top and the two bottom.

 

36x^2/25

 

Hope that helps.

 

 

 

 

Answer 2

Squaring means to mutiply and expression by itsel.

 

(2x + 9)²

(2x + 9)(2x + 9)

4x² + 18x + 18x + 49

4x² + 36x + 49