Solve for x, given the equation squaroot of x - 5 + 7 = 11.

x = 21, solution is extraneous
x = 21, solution is not extraneous
x = 81, solution is extraneous
x = 81, solution is not extraneos

Question

Solve for x, given the equation squaroot of x - 5    + 7 = 11.

x = 21, solution is extraneous
 x = 21, solution is not extraneous
 x = 81, solution is extraneous
 x = 81, solution is not extraneos

tkhunny · Answer

You must communicate better than that and you are making efforts to do so.  Excellent!

Subtract 7 from both sides and then stop to think about it.

anonymous · Answer

$$\sqrt{x-5}$$ + 7=11

anonymous · Answer

like minus 7 from $$\sqrt{x-5}$$

tkhunny · Answer

Please don't use "minus" like that.  The word "subtract" actually means what you want.

$\sqrt{x-5} + 7 = 11$

Subtract 7 from each side.

7 - 7 = ??
11 - 7 = ??

anonymous · Answer

$$\sqrt{x-5}=4$$

tkhunny · Answer

Perfect.  Now the thinking part.

If that square root is going to work, what do we know about "x-5"?

anonymous · Answer

i do not know to be completely honest, but wouldnt you square both sides of $$\sqrt{x-5} =4$$

anonymous · Answer

@tkhunny

tkhunny · Answer

You can do that, but it is MUCH wiser to think about it first.  Answer my question!

If the square root is to work, then $x-5 \ge 0\;or\;x \;\ge \;5$

Does that make any sense?