Question

sqrt{x + 2} = x - 4

Find x (which is 7).

Answer 1

@math0101 Square both sides, can you?

Answer 2

x + 2 = x2 - 8x + 16

Answer 3

Great :)
Now simplify it into quadratic form >)

Answer 4

hmm

x + 2 = (x - 4 )^2

Answer 5

still stuck :)

Answer 6

x^2 - 8x - x + 16 -2 = 0
Add them together

Answer 7

aha!

x^2 - 9x -14 = 0

x = 9/2 +- sqrt{(9/2)^2 + 14}

x = 9/2 0- 5/2

x1 = 7
x2 = 2

x1 is correct, but for some reason my book doesn't mention x2

Answer 8

x = 9/2 0- 5/2 SHOULD READ:

x = 9/2 +- 5/2

Answer 9

I think I'll mark this as done. :) Thank you!

Answer 10

Now pay attention to validate the solutions in square root case!

Answer 11

oh yes... so much to remember!

Like learning a language ;)

Thanks!

Answer 12

Domain: x ≥ 4