SOLUTION
Part A
From the question,
Green lawn charges $49 + $29 per month and
Grass team charges $25 + $37 per month
Let the number of month they will charge the same be x, then in x month, they both will charge
[tex]\begin{gathered} 49+$29$x\text{ and } \\ 25+$37$x \\ \text{For them to charge the same, } \\ 49+$29$x=25+$37$x \end{gathered}[/tex]
Solving for x, we have
[tex]\begin{gathered} 49+$29$x=25+$37$x \\ 49-25=37x-29x \\ 24=8x \\ \frac{24}{8}=\frac{8x}{8} \\ 3=x \\ x=3 \end{gathered}[/tex]
Hence, they will cost the same in 3 months
Part B
The cost will be
[tex]\begin{gathered} 49+29x \\ 49+29\times3 \\ 49+87=136\text{ or } \\ 25+37x \\ 25+37\times3 \\ 25+111=136 \end{gathered}[/tex]
Hence the answer is $136
Part C
If the family use the service for only 6 months, then
For Green Lawn, the cost would be
[tex]\begin{gathered} 49+$29$x \\ x\text{ will be 6 months } \\ 49+29\times6 \\ 49+174=223\text{ dollars } \\ \end{gathered}[/tex]
Hence, Green Lawn will cost $223
For Grass Team, the cost would be
[tex]\begin{gathered} 25+$37$x \\ x\text{ will be 6 months } \\ 25+$37$\times6 \\ 25+$222$=247\text{dollars } \\ \end{gathered}[/tex]
Hence Grass Team will cost $247
Hence Green Lawn is a better option, since it is cheaper