Question

I know this is probably basic stuff to know but how do I find the domain of 3x^2+5x+2? I'm going over an exam review and I want to make sure I'm doing everything correctly

Answer 1

The domain is the set of allowable inputs for the function, the function here being
f(x) = 3x^2 + 5x + 2

The set from which we draw allowable inputs is implied here to be the real numbers. Now we ask ourselves , are there any inputs which not allowed. I don't see any reason why i can't plug in any number for x, so the set of allowable inputs is all real numbers.

A reason where a function does not have an allowable input, is for example f(x) = 1/ x. Then if x = 0, you have division by zero which is undefined (no y value).

So another way of looking at it, the domain is all x values for which there is a 'defined' y value . ie the y value is not blank

Answer 2

Would the x-intercepts be -1, -2/3?

Answer 3

(3x+2)(x+1) then I set both equal to zero

Answer 4

you are right, i graphed it incorrectly

Answer 5

x intercepts are the points common to both x axis and the graph of your function

Answer 6

for some reason i thought the function was above the x axis, weird :D