Answer:
2 works
-3 is extraneous
Step-by-step explanation:
sqrt(x + 7) - 1 = x Add 1 to both sides
sqrt(x + 7) = x + 1 Square both sides
(x + 7) = (x + 1 )^2
x + 7 = x^2 + 2x + 1 Subtract x from both sides
0 = x^2 + x + 1 -7
0 = x^2 + x - 6 This will factor
(x + 3)(x - 2) = 0 Find the values for x
x + 3 = 0
x = - 3
x - 2 = 0
x = 2
Now you must check this to see if both values work
sqrt(-3 + 7) - 1 = -3
sqrt(4) - 1 = -3
2 - 1 =? - 3
1 does not equal - 3. Therefore - 3 is extraneous. Try x = 2
sqrt(2 + 7) - 1 = 2
sqrt(9) - 1 = 2
3 - 1 = 2
2 = 2
