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vivalakodaBest ResponseYou've already chosen the best response.0
\[4\sqrt{x+9}=20 \]
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
I know how to solve is, I'm just not sure how to get rid of the 4 in the front of the radical.
 one year ago

Ladyalice25Best ResponseYou've already chosen the best response.0
you need to remove the square from x+9 the way you do that is by squaring both side and you end up with x+9=(20/4)^2. then solve from there.
 one year ago

Ladyalice25Best ResponseYou've already chosen the best response.0
x+9=20/4)^2. 20/4^2 = 25 then take 25 subtract 9. you will get the answer of x=34
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
it's easy to see that this has NO SOLUTION: (4)*(5) = 20 so that means: \(\large 4\sqrt{x+9}=20 \rightarrow \sqrt{x+9}=5\) \(\large \sqrt{x+9}=5\) which has no solution because the left side is always positive but the right side is negative
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
Can't you just square both sides to get rid of the square root, then solve like an equation?
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
yes you can try to do that... it's one technique you should try to solve it. but why continue when you know this is an impossible equation to solve?
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
not impossible, no solution... if you do solve it, the solution is an extraneous solution....
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
If according to your answer it is √x+9 = 5 then you'd square both sides to have: x+9 = 25 subtract 9 from both sides and get 16 as x?
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
Difficult equation in history
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
squaring both sides you get positive 25
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
Oh, that's right thanks so then x+9=25 subtract 9 then positive 16?
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
yes... now let's see if the solution of x=16 works....
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
\(\large (4)(\sqrt{x+9})=20 \) \(\large (4)(\sqrt{\color {red}{16}+9})=20 \) \(\large (4)(\sqrt{\color {red}{25}})=20 \) \(\large 4 \cdot 5 = 20 \) \(\large 20=20 \) ???? not a true statement
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
so the solution of x=16 is extraneous and not really a solution.
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
solution \[\left 4 \right\]
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
@AntarAzri , what's the solution?
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
\[\left 4 \right\]
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
\(\large (4)(\sqrt{x+9})=20 \) \(\large (4)(\sqrt{4+9})=20 \) \(\large (4)(\sqrt{4+9})=20 \) \(\large (4)(\sqrt{13})=20 \) x=4 doesn't seem to work. That's not a solution.
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
my oh my I have headaches because of this problem..
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
no no i dont mean the x −4=4
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
ok. whatever... my answer stands... NO SOLUTION to the equation: \(\large (4)(\sqrt{x+9})=20 \) \)
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
\[(\left 4 \right)(\sqrt{16+9})=20\]
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
here's wolframs answer: http://www.wolframalpha.com/input/?i=solve+4*sqrt%28x%2B9%29%3D20
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
http://www.wolframalpha.com/input/?i=solve+%E2%88%924*sqrt%28x%2B9%29%3D20
 one year ago

dpaIncBest ResponseYou've already chosen the best response.2
if u don't understand my answer and expanation maybe someone else can give u a better answer... i will not argue my point further....
 one year ago

AntarAzriBest ResponseYou've already chosen the best response.0
Do we agree that it can not be the root of a negative number gives a positive number ?
 one year ago

vivalakodaBest ResponseYou've already chosen the best response.0
I'll see what my teacher says when she grades it. Thanks for your time
 one year ago
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