Question

Find the solution(s): sqrtx+9+sqrtx=9

Answer 1

I saw your name and had no choice but to answer this now...to bad I don't understand the question :s

Answer 2

Heh

Answer 3

\[\sqrt{x+9}+\sqrt{x}=9\]right?

Answer 4

Yes

Answer 5

square both sides,
using \[(a+b)^2=a^2+2ab+b^2\]for the left side,\[(x+9)+(2 \times \sqrt{x+9} \times \sqrt{x})+x=81\]

Answer 6

\[2x+9+2\sqrt{x^2+9x}=81\]

Answer 7

\[2\sqrt{x^2+9x}=-2x-9+81\]\[2\sqrt{x^2+9x}=-2x+72\]\[2~~(\sqrt{x^2+9x})=2~~(-x+36)\]\[\sqrt{x^2+9x}=-x+36\]

Answer 8

square both sides,\[x^2+9x=x^2-72x+1296\]\[81x=1296\]\[x=16\]

Answer 9

Wow

Answer 10

The reason why I'm confused with this is because my teacher taught it to me differently and I don't get how she got the answer. Can I show you the way she did it?

Answer 11

sure.

Answer 12

I'll be back in short...

Answer 13

Ok

Answer 14

The first thing she did was she subtracted sqrtx from the left side. Then she squared each side to get rid of the radical and I get x+9 = 81-x. Then I subtract 9 from both sides and add x to both sides and then divide both sides by 2 and get 36 but I already know that's the wrong answer.

Answer 15

\[(9-\sqrt{x})^2~~~????????\]What a poor teacher, she forgot about the middle term.

Answer 16

Even a 16 year old like me knows this, common teacher.....

Answer 17

brb one sec