The expression that can be used in order to express the amount of money that Morgan has after spending s will be,
x = 150 - s
where x is a variable that we can use in order to denote the amount she will have left, 150 is the original amount of money as stated in the problem and s is the amount spent.
For the evaluation, we simply have to substitute the given values in place of s and calculate for the value of x.
(1) s = $27.13
x = 150 - 27.13
x = $122.87
(2) s = $55.14
x = 150 - 55.14
x = $94.86
