"45 dollars more": +45
Total spent: 79.50
x=jeans
x+(45+x)=79.50
2x+45=79.50
2x=79.50-45
2x=34.5
x=34.5/2
x=17.25
This means that the jeans were $17.25 a pair.
Thus, $45+$17.25 = $62.25, so we can check:
$62.25+$17.25 = $79.50
Thus the jeans were $17.25.