In order to find the number of units that Marcela can take for her college classes, we can set up an inequality and solve for the variable. Since each unit costs $105, we can say that 105u ≤ 1365 where u = the number of units. The number of units multiplied by the cost per unit, must be less than or equal to $1,365. In order to solve for 'u', we can use inverse (opposite) operations and get rid of the coefficient by dividing both sides of the inequality by 105. 1365÷105 = 13. So, the number of units that Marcela can take must be less than or equal to 13 units.