sqrt (t) = sqrt (t - 12) + 2? solve the radical equations, of possible.

2 Answers
Apr 16, 2017

THIS ANSWER IS INCORRECT. SEE THE CORRECT SOLUTION ABOVE.

Explanation:

Start by squaring both sides to get rid of one of the radicals, then simplify and combine like terms.
sqrtt^color(green)2=(sqrt(t-12)+2)^color(green)2
t=t-12+4sqrt(t-12)+4
t=t-8+4sqrt(t-12)

Then operate on both sides of the equation to isolate the other radical.
tcolor(green)(-t)=color(red)cancelcolor(black)t-8+4sqrt(t-12)color(red)cancelcolor(green)(-t)
0color(green)(+8)=color(red)cancelcolor(black)("-"8)+4sqrt(t-12)color(red)cancelcolor(green)(+8)
color(green)(color(black)8/4)=color(green)((color(red)cancelcolor(black)4color(black)sqrt(t-12))/color(red)cancelcolor(green)4
8=sqrt(t-12)

And square both sides again to get rid of the other radical.
8^color(green)2=sqrt(t-12)^color(green)2
64=t-12

Finally, add 12 to both sides to isolate t.
64color(green)(+12)=tcolor(red)cancelcolor(black)(-12)color(red)cancelcolor(green)(+12)
76=t
t=76

When working with radicals, always check your solutions to make sure they aren't extraneous (make sure they don't cause there to be a square root of a negative number). In this case both 76 and 76-12 are positive, so 76 is a valid solution for t.

Apr 17, 2017

x in {16}

Explanation:

Rearrange the equation:

sqrt(t) - 2 = sqrt(t - 12)

Square both sides:

(sqrt(t) - 2)^2 = (sqrt(t - 12))^2

t - 4sqrt(t) + 4 = t - 12

Simplify:

16 = 4sqrt(t)

4 = sqrt(t)

Square both sides once more.

16 = t

Check the solution is accurate.

sqrt(16) = sqrt(16 - 12) + 2 -> 4 = 4 color(green)(√)

Hopefully this helps!