Question 189906
Graph each equation using a graphing calculator. Choose which function is an inverse variation. 

a. {{{ y=5/x }}}
b. {{{ y=13x^2 }}}
c. {{{ y/x=5 }}}
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I graphed them.  How will that help you?
a is an inverse relation, as x increases, y decreases.
c appears to be inverse, but can be written as y = 5x, not inverse.