Question

find solutions for 9x^2-81=0

Answer 1

x = 3 or -3

Answer 2

x^2=9 and so u get x=+3 and x=-3

Answer 3

x^2-9
(x+3)(x-3)=0

Answer 4

(3x+9)(3x-9)
so x = -9 or 9

Answer 5

what about for x^2-9=0, will that also be -3 and3

Answer 6

yes

Answer 7

use the difference of 2 squares
why? 9x^2 is a square
and 81 is a square
difference = -
sqr root 9x^2 =3x
sqr root 81=9
answers are solutions to (3x+9)(3x-9)=0
3x+9=0 implies 3x=-9 implies x=-3
and 3x-9 implies 3x=9 implies x=3
answers as given earlier x=3 or -3

Answer 8

x^2-9=0
sqr root x^2 is x
sqr root of 9 =3
0=(x+3)(x-3)
x=3 or -3 yes the answers are the same.