The first thing you should do is to<span> divide the total cost by the unit cost you have got: </span><span>(2y^2 + 6) / (y^2 - 1) </span> Then just use simple math by plugging in the value y=3 (2*3²+6): (3²-1)= 24:8 = 3 which is the nubmer of the bought notebooks.
<span>In total he spent $24 on notebooks that cost $8.</span>
