Part A. Define the variables and the equation.
Let y be the money Ling wants to save and x be the weeks, then we can write
[tex]y=4x+23[/tex]
Part B. Solve the equation.
Since Ling wants $87, then y=87. By substituting this value into the last equation, we get
[tex]87=4x+23[/tex]
then, by moving 23 to the left hand side, we have
[tex]\begin{gathered} 87-23=4x \\ 64=4x \end{gathered}[/tex]
or equivalently,
[tex]4x=64[/tex]
Finally, by moving 4 to the right hand side, we obtain
[tex]\begin{gathered} x=\frac{64}{4} \\ x=16 \end{gathered}[/tex]
Then, How long will it take her to get enough money to buy the tickets? 16 weeks
