Answer:
See below in bold.
Explanation:
Let t be the number of tulips you buy and r be the number of rose bushes.
a.
The system is:
t + r = 13
4t + 10r = 100
b.
Solving:
4t + 10r = 100
t + r = 13 Multiply this by 4:
4t + 4r = 52 Subtract this from the first equation:
0 + 6r = 48
r = 8.
Now substitute for r in t + r = 13:
t + 8 = 13
t = 5.
c.
To buy 13 plants and spend $100 you need to buy 5 tulips and 6 rose bushes.