Thank you. Hey No, This is not a school assignment!I think the gain is clearly spelled out in the datasheet, attached.
Is this a school assignment?
So output voltage is 15 times 100mV ryt? 1.5VThe Texas Instruments datasheet has a graph in figure 12 that shows a gain at low frequencies that would be 15 times (but 18 times at 80MHz) on your non-differential circuit if the input resistors are 50 ohms.