Can someone check my work? Interval notation? Will Post below.

Question

blondie_b23 · Answer

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amit1235813 · Answer

Um, domain is the value that x can take. In question 8, x can take any value.

blondie_b23 · Answer

Can you explain what I should have done instead? and how do you know it can take any value? I really don't understand. @admit1235813

sshayer · Answer

$$h(x)=x^2-9,- \infty <x< \infty$$

sshayer · Answer

$$z(x)=\frac{ 4 }{ x^2+9 },x^2 \geq 0 ~for~ all ~x$$
z(x) is defined for all x
so domain is all real numbers

blondie_b23 · Answer

I'm so confused. I really don't understand this concept.

sshayer · Answer

$$x^2+9 \geq9 \neq 0$$
so denominator is not zero for any value of x
domain is all real numbers or$$-\infty <x<\infty $$

amit1235813 · Answer

For part a, domain is all real numbers
@sshayer is talking about part b

amit1235813 · Answer

*I meant the question of left and right