Write a system of equations using A and B as the variables
The first equation is the sum of the lengths of the plants
The second equation is the relation of growth that plant A grew 5cm more than plant B
Insert the second equation into the first one to solve for B
Solve the equation for B
Use the value of B in the second equation to find the value of A
Plant A is 23 cm long on Tuesday and plant B is 18 cm long on Tuesday.