For the given question, Let x represent the number of weeks and y represent the total amount of money in the account.
Peter and Sam both opened a savings account when they got their first job.
Peter started with 150 in his account and deposits $30 each week.
So, the equation of Peter will be:
[tex]y_1=30x+150[/tex]Sam started with $90 in his account and deposits $45 each week.
So, the equation of Sam will be:
[tex]y_2=45x+90[/tex]2. we will find when Peter and same will have the same amount in their account
so,
[tex]\begin{gathered} y_1=y_2 \\ 30x+150=45x+90 \end{gathered}[/tex]Solve the equation to find the value of (x):
[tex]\begin{gathered} 30x-45x=90-150 \\ -15x=-60 \\ \\ x=\frac{-60}{-15}=4 \end{gathered}[/tex]Substitute with (x) into equation y1 or y2 to find the amount in their account
so,
[tex]y_1=30\cdot4+150=120+150=270[/tex]So, the answer will be:
Peter and same will have the same amount in their account at 4 weeks. At this time they will both have $270 in their accounts