Let h be the hours and y the total charge. Then, for Happy Paws, we have
![y=2.50h+19](https://img.qammunity.org/2023/formulas/mathematics/high-school/o8ic4pk0pi0d2k2za8xhyp1xp16tq8mnfy.png)
and for Woof Watches, we have
![y=3.75h+10](https://img.qammunity.org/2023/formulas/mathematics/high-school/1txxaly6vyykptkjt6yt8g67qv15xa2sza.png)
Then, we need to solve these equations.
Solving by elimination method.
If we multiply by -1 the first equation, we have the equivalent system of equations:
![\begin{gathered} -y=-2.50h-19 \\ y=3.75h+10 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/bkhq6ih3f231s3h2lvcuzaup4qn9erwgnn.png)
If we add both equations, we obtain
![0=(3.75-2.50)h+10-19](https://img.qammunity.org/2023/formulas/mathematics/high-school/wos5wr2p8p26x1hmlpqtj0g5vxczrt85l7.png)
because y-y=0. Then, it yields,
![0=1.25h-9](https://img.qammunity.org/2023/formulas/mathematics/high-school/w1vhmms0f8jtyo0cfvp3suf5qmuxwrmn5u.png)
If we move -9 to the left hand side as -9, we have
![\begin{gathered} 9=1.25h \\ h=(9)/(1.25) \\ h=7.2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/y909693o495frun87z5nnpfzx9i400furd.png)
Hence, to find the total cost, we must substitute this values into one of the 2 equations. If we choose the first one, we obtain
![\begin{gathered} y=2.50(7.2)+19 \\ y=18+19 \\ y=37 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/c8bc45qzu5nxh1ngopnrcd38jkwtftlril.png)
Then, the answers are:
The equation is
![2.50h+19=3.75h+10](https://img.qammunity.org/2023/formulas/mathematics/high-school/tkn82nqto1h6p0yh3le9s79d3w07spnt13.png)
and, the total cost of the services will be equal at 7.2 hours