Question

Determine if the following is always, sometimes, or never true.
y = -1/5 x + 3 is a function.
Answer

Always

Sometimes

Never

Answer 1

For any value of 'x' that you put in...will it give you it's own unique 'y' value?

Answer 2

i am sure this is not the answer your math teacher wants, but
\[y=-\frac{1}{5}x+3\] is NEVER a function, it is an equation !!

Answer 3

Good point @satellite73 lol

Answer 4

thus begins the long and understandable confusion in unsuspecting students about the difference between a function and an equation

Answer 5

i blame your math teacher

Answer 6

if you want to write a function, you have to write a function
you can say
"let \(f(x)=-\frac{1}{5}x+3\)" for example

Answer 7

so it is an equation?

Answer 8

or you could say
let the function \(f\) be defined by the set of ordered pairs \(\{(x,y):y=-\frac{1}{5}x+3\}\)

Answer 9

yes, it is an equation
and i am afraid your math teacher wants you to also say it is a function, since each \(x\) values determines a unique \(y\) value
it is wrong
very wrong
but that is the answer they want "yes"

Answer 10

Q: If the problem is under the form you said, is it always a function? how to test?