Answer:
Cost of one rose bush: $10
Cost of one shrub: $4
Explanation:
1. You must make a system of equation, where
is the cost of one rose bush and
is the cost of one shrub.
2. You know that Rob spent $100 on 8 rose bushes and 5 shrubs and Amy spent $112 on 8 rose bushes and 8 shrubs, therefore, you have.

3. Apply the Substitution method. Multiply the first equation by -1, add both equations and solve for y:

4. Substitute y into one of the equation and solve for x:
