Question

What is the solution of the equation? √2x+13-5=x

Answer 1

Take all x terms to one side and constant to other side

Answer 2

\[\sqrt{2x+13}-5=x\]??

Answer 3

I got x=-6 and -2, is that right?

Answer 4

@satellite73

Answer 5

-6 wont work

Answer 6

why?

Answer 7

i assume you squared at one point and then solved a quadratic equation right?

Answer 8

i think so

Answer 9

when you square , you can introduce an extraneous solution
just like you know \(-5\neq 5\) but \((-5)^2=5^2\)

Answer 10

the point is that you have to check your answers against the original equation

Answer 11

that's confusing,,

Answer 12

\[\sqrt{2x+13}=x+5\] put \(x=-6\) get \[\sqrt{2\times (-6)=13}=-6+5\]
\[\sqrt{1}=-1\] which is false

Answer 13

the second?

Answer 14

\(-2\) should work

Answer 15

\[\sqrt{2\times(-2)+13}=-2+5\]
\[\sqrt{9}=3\] which is true

Answer 16

point is that when you square as one step, you have to check your solutions in the original equation to make sure they both work

Answer 17

they both might work, or maybe one works and one does not

Answer 18

oh okay so the answer is -2?

Answer 19

@satellite73

Answer 20

yes

Answer 21

okay thank you!!