Question 200588
sqrt(-w)  -6 =w
sqrt(-w) = w+6
SQUARE  BOTH  SIDES
(-w) = (w+6)^2 = w^2 +12w +36
0 = w^2 +13w +36
FACTOR
0 = ( w+9)(w+4)
(w+9) =0,,,w=(-9),,,,,,,(w+4)=0,,,,,w=(-4),,,,so  far  ok  to  advise  
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Checking
w=-4,,,,,sqrt -(-4)  -6 = (-4)
sqrt(+4) -6 = -4
+2 -6 = -4,,,,,,ok,,,,,,,,,,,,,,,,,,pls  note,,,,,,opposite  advise
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w=(-9),,,,,,sqrt -(-9) -6 = (-9)
sqrt (+9) -6 = (-9)
3 - 6 = -9
-3 = -9,,,,,NO,,,,,,therefore  not  answer,,,,,note,,,opposite  advise