SOLUTION: Solve the radical equation, and check ALL proposed solutions: sqrt(x+6) + sqrt(2-x) = 4 Answer choices: A.) {2, -2} B.) {0} C.) {sqrt(31), -2} D.) {-2} Thanks!

Algebra ->  Radicals -> SOLUTION: Solve the radical equation, and check ALL proposed solutions: sqrt(x+6) + sqrt(2-x) = 4 Answer choices: A.) {2, -2} B.) {0} C.) {sqrt(31), -2} D.) {-2} Thanks!      Log On


   



Question 340744: Solve the radical equation, and check ALL proposed solutions:
sqrt(x+6) + sqrt(2-x) = 4
Answer choices:
A.) {2, -2}
B.) {0}
C.) {sqrt(31), -2}
D.) {-2}
Thanks!

Answer by Sphynx pinastri(7) About Me  (Show Source):
You can put this solution on YOUR website!
First, re-write the equation for clarity
sqrt%28x%2B6%29+%2B+sqrt%282-x%29+=+4
and square both sides
x%2B6+%2B+2-x+%2B+2sqrt%28%28x%2B6%29%282-x%29%29+=+16
simplify
sqrt%28%28x%2B6%29%282-x%29%29+=+4
and square both sides
%28x%2B6%29%282-x%29+=+16
multiply
2x+-+x%5E2+%2B+12+-6x++=+16
simplify
x%5E2+%2B+4x+%2B+4+=+0
notice that the equation is
%28x%2B2%29%5E2+=+0
i.e.
x+=+-2
So the answer is D
In general you get rid of the radicals and solve the resulting equation.
When the equation cannot be easily solved, try to guess the rational roots
and simplify the equation.