Solve for x. Identify if extraneous or not. Show work.
-4(sqrtx+9)=20

Please help!! I am so lost :(

Question

Solve for x. Identify if extraneous or not. Show work. 
-4(sqrtx+9)=20

Please help!! I am so lost :(

anonymous · Answer

is it 
$$-4\sqrt{x+9}=20$$?

anonymous · Answer

Yeah

anonymous · Answer

I don't understand... How can you go from that whacky 5 letter variable to just x?

anonymous · Answer

sqrt is short for square root

anonymous · Answer

oh lol, fair enough

anonymous · Answer

easy

anonymous · Answer

Help me please I really don't get imaginary numbers

anonymous · Answer

sec

anonymous · Answer

hmmmm, well to be totally honest, I haven't exactly learnt imaginary numbers yet lol. I am getting x=sqrt -8

anonymous · Answer

is that similar to your answer so far?

anonymous · Answer

I was getting like x=-5i but that 9 is messing me up

anonymous · Answer

mm another way that I can work it out results in x=sqrt-5 -9

anonymous · Answer

Yeah but I need an imaginary number (i) to get the negative four to turn into a positive number when multiplied by the radical

tkhunny · Answer

What are you doing?

$-4\sqrt{x+9} = 20$ has no solution at all, Real, Complex, or otherwise.  This is obtained by inspection.

By definition, $\sqrt{x+9} \ge 0$ -- Done!