Question

Which method would you use to solve the problem substitution or graphing explain your answer (PART B)

Answer 1

Based on the solution that is being on Part A, the method used is substitution.

Step-by-step explanation:

The two equations in Part A were:

x = the number of weeks

Equation 1: Lyle's savings = 100 + 20x

Equation 2: Shaun's savings = 500 + 10x

Since we wanted to know when Lyle's and Shaun's savings will be equal, we substituted "Lyle's savings" in the equation with 500 + 10x. It made equation 1 become 500 + 10x = 100 + 20x.

Or, we substituted "Shaun's savings" in the equation with 100 + 20x. It made equation 2 become 100 + 20x = 500 + 10x.

From this, we were able to calculate that at week 40, both Lyle and Shaun will have the same amount in their savings account.

`\begin{gathered} 500+10x=100+20x \\ 500-100=20x-10x \\ 400=10x \\ (400)/(10)=(10x)/(10) \\ 40=x \end{gathered}`