How do you solve $abs(x^2 - 9 )= x^2 - 9$ ?

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Answer 1 · 2018-07-10T07:49:49

The solutions are $S={-3,3}$

The equation is

$|x^2-9|=x^2-9$

Therefore,

${(x^2-9=x^2-9),(x^2-9=-x^2+9):}$

$<=>$ , ${(O/),(2x^2-18=0):}$

$<=>$ , ${(O/),(x^2-9 =0):}$

$<=>$ , ${(O/),((x+3)(x-3) =0):}$

$<=>$ , ${(x=-3),(x=3):}$

The solutions are $S={-3,3}$

How do you solve abs(x^2 - 9 )= x^2 - 9abs(x^2 - 9 )= x^2 - 9?