Is joshs solution for the equation x^2-6x-7=0: x^2-6x-7=0
x^2-6x=7
x^2-6x+9=7+9
(x-3)^2=16
x=19
x-3=-16
x=-13
is joshs solution correct? explain

  no. see below

Step-by-step explanation:

This much of Josh's working is correct:

  x^2-6x=7

  x^2-6x+9=7+9

  (x-3)^2=16

At this point Josh apparently overlooked the fact that he needed to take the square root of both sides of the equation. Had he done that, he would have ...

  x -3 = ±4

  x = 3+4 . . . or . . . 3 -4

  x = 7 or -1

Josh reported values of x that would match ...

  x -3 = ±16

He violated the equal sign by taking the square root on the left, and multiplying by ±1 on the right. Doing different operations on the two sides of the equation will mean the value of x is changed to something other than what you're looking for.

the 3rd option is right

step-by-step explanation: