Answer:
a) Let's define the variables:
t = number of tulips bought
r = number of roses bought
We know that each tulip costs $5, and each rose costs $3.
Then the total cost will be:
$5*t + $3*r
We know that Morty spent a total of $54, then we have the equation:
$5*t + $3*r = $54
We also know that he bought a total of 14 flowers, then:
r + t = 14
Then the system of equations is:
$5*t + $3*r = $54
r + t = 14
b) To solve the system, first, we need to isolate one of the variables in one of the equations. I will isolate r in the second one:
r = 14 - t
Now we can replace this into the other equation:
$5*t + $3*r = $54
$5*t + $3*(14 - t) = $54
Now we can solve this for t.
$5*t + $3*14 - $3*t = $54
$2*t + $42 = $54
$2*t = $54 - $42 = $12
t = $12/$2 = 6
t = 6
He bought 6 tulips.
Now we can use the equation r = 14 - t
r = 14 - 6 = 8
r = 8
He bought 8 roses.