How do I find the domain of #f(x)=2x+3#?

1 Answer
MrsRudolph221
Sep 7, 2014

The domain for a linear function like y = 2x + 3 is all real numbers. I ask that students write: #(-\infty,\infty)#

I remind my students that any number can be multiplied by 2 and have 3 added to the result. There is no problem substituting in positive numbers, negative numbers, irrational numbers or basically any real number!

The graph also shows students that it heads both directions infinitely. Left and down, and right and up! This knowledge will help you to describe the function's end behavior and range as well.

my screenshot

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