math help me?

Question

xsquared + (x+3)squared=225
what is x

where did the 6x come from

Answer 1

x^2 + x^2 + 6x + 9 = 225
x^2 +3x=108
x^2 + 3x - 108 = 0
(x + 12) (x - 9) = 0
x= - 12; x =9

Answer 2

X^2 + (x+3)^2 = 225
X^2 + X^2 + 6x + 9 = 225
2x^2 +6x -216 = 0
X^2 + 3X - 108 = 0
(X+12)(X-9) = 0
X = -12 or X = 9

Man, I hate when I try answer I question that it looks like nobody else answered and by the time I type in the answer, eight other people already posted!!!!

Answer 3

9

Answer 4

x^2 + (x+3)^2 = 225
x^2 + (x^2 +6x + 9) = 225
x^2 + x^2 + 6x + 9 - 225 = 0
2x^2 + 6x - 216 = 0
x^2 + 3x - 108 = 0
use either factoring, or quadratic equation to get the value of x.
x^2 + 3x - 108 = (x - 9) (x + 12)
x = 9, -12

Answer 5

lol i think this is why i couldnt figure out the other problem! (u had 2x^2)!


x^2 + x^2+6x+9 = 225

2x^2 + 6x + 9 = 225

2x^2 + 6x - 216 = 0

divide everything by 2

x^2 + 3x - 108 = 0

(x +12) (x-9) =0


x= -12, x = 9

YAY!

Answer 6

My answer is within your other question but the 6x you get from FOILING (x+3) when you square it:

(x+3)(x+3) = x^2 + 3x + 3x + 9 = x^2 + 6x + 9

I see you changed the problem too.

x = -12 or x = 9

Answer 7

x=9 , -12

if you have a ti83/84 you can do this by going to the Y=

1.Press Y=
2.Put in --- X^2+(X+3)^2 --- in the Y1 spot
3.Put in --- 225 --- in the Y2 spot
4.Press 2nd Graph(Table)
5.Now Look for the same answer in the Y1 and Y2
6.Match the 225 in the Y2 up with the 225 in the Y1
7.Doe this for both the (-) and (+) X
8.Now Look look in the X col. and that is you answer


This may work for any graphing clac. IDK

Answer 8

FOIL the (x+3)^2

then add all the pieces up so that you have ax^2+bx+c=0

then use the quadratic formula

see this site for reference
http://www.purplemath.com/modules/quadform.htm