+0

I need an easier way

+1
391
7
+578

So I know how to simplify something like

$$(x+7)(x-7)=x^2-49$$

but can someone give me an easy way to simplify something like

$$(2x-3i)(2x+3i)(x+8)(x+2)=?$$

and I'm also going to ask another question about that math problem when I get this answer, so be warned.

Oh! If anyone needs a tip on LaTeX use, message me.

Dec 1, 2017

#1
+101055
+3

$$(2x-3i)(2x+3i)(x+8)(x+2)\\ =(4x^2-9i^2)(x+8)(x+2)\\ =(4x^2+9)(x+8)(x+2)\\ =(4x^2+9)(x^2+10x+16)\\ =4x^2(x^2+10x+16)\quad +\quad 9(x^2+10x+16)\\ etc$$

.
Dec 1, 2017
#2
+578
+2

I'm sorry, but I need a full polynomial form, not factored form.

#3
+101055
+2

Just expand it our and then collect like terms.  I thought you cold do that yourself :/

Melody  Dec 1, 2017
#4
+578
+3

idk how with polynomials...

#5
+578
+2

and im kinda full with a lot of math at once

#6
+101055
+3

$$=4x^2(x^2+10x+16)\quad +\quad 9(x^2+10x+16)\\ =4x^4+40x^3+64x^2\quad +\quad 9x^2+90x+144\\ =4x^4+40x^3+73x^2+90x+144\\$$

Melody  Dec 1, 2017
#7
+578
+3

thanks