Question

which is the extraneous solution of -x = sqrt(2x +15)

Answer 1

a) -5
b) -3
c) 3
d) 5

Answer 2

What is the extraneous solution

Answer 3

square both sides

Answer 4

You basically want to see which of those is a solution to
\[x^2=2x+15 \text{ but \not a solution to } -x=\sqrt{2x+15}\]

Answer 5

So the answer is 5

Answer 6

sounds great! :)

Answer 7

that are two soluitions to x^2-2x-15=0
(x+3)(x-5)=0
x=-3 or x=5
we see the 5 definitely won't work because there is no way sqrt() will produce a negative number

Answer 8

\[-x=\sqrt{2x+5} \text{ means } x \text{ is negative }\]

Answer 9

anyways great job