Answer
a. $x=\pm 2$
b. $x=\pm 2$
c. $x=\pm 2$
d. $x<-2, x>2$
e. $x\leq -2,x\geq 2$
f. $x<-2,x>2$
g. $x \leq -\sqrt 5,x\geq \sqrt 5$
Work Step by Step
$f(x)=x^2-4,$
$g(x)=-x^2+4,$
a. $x^2-4=0,$
$x^2=4,$
$x=\pm 2$
b. $-x^2+4=0,$
$-x^2=-4,$
$x^2=4,$
$x=\pm 2$
c. $x^2-4=-x^2+4,$
$2x^2=8,$
$x^2=4,$
$x=\pm 2$
d. $x^2-4>0,$
$x^2>4,$
$x<-2, x>2$
e. $-x^2+4\leq 0,$
$-x^2\leq -4,$
$x^2\geq 4,$
$x\leq -2,x\geq 2$
f. $x^2-4> -x^2+4,$
$2x^2>8,$
$x^2>4,$
$x<-2,x>2$
g. $x^2-4\geq 1,$
$x^2\geq 5,$
$x \leq -\sqrt 5,x\geq \sqrt 5$
