Second, third and fourth set of ordered pairs does not represent a function so only the first one is a function. This is because each x value has to has their distinct y value. So you notice all sets of ordered pairs except the first one, two different x-values have the common y-value, which cannot be happen.
The quickest method to use is to put "0" in for <em>y</em><em>,</em><em> </em>then figure out which term for <em>x</em> would make the equation authentic, or genuine.
