Question

√(x+16)=x+4

Answer 1

\[\sqrt{x+16}=x+4\]

Answer 2

square both sides
x+16=(x+4)^2
(x+4)^2 is the same as (x+4)(x+4)= x^2+8x+16
x+16=x^2+8x+16
subtract both sides by 16
x=x^2+8x
subtract both sides by x
0=x^2+8x-x
8x-x=7x
0=x^2+7x
Factor out an x
0=x(x+7)

Now you have to find at what value of x the equation is equal to 0.

The obvious one is x=0
because:
0*(0+7) is 0

The other one is x=(-7)
-7*(-7+7)=-7*(0)=0

So x= -7, 0

Answer 3

whoa, are you wearing a bra

Answer 4

x=0 is correct. Radical 16 = 4.

at x=-7, 3 radical 9 is not equal to -3

Answer 5

"3 radical 9" should have been posted as "radical 9"

Answer 6

wait WHAT?

Answer 7

There is no negative sign, explicit or inferred as far as I can see, in front of the radical sign in your problem statement. If you replace x with -7 in your problem equation and do the math, you will get on the left hand side,
\[\sqrt{-7+16}=3 \]
On the right and side you will get -7+4=-3. 3 is unequal to -3. In other words -7 is not a solution to the problem as presented.