29. The monthly rent for an $\mathbf{8}\mathbf{0}\mathbf{0}$ square foot office is $\mathrm{\$}975$. For an 1100 square foot office, the rent is $\mathrm{\$}1125$. Write and solve a linear equation to find the monthly rent for a 1500 square foot office.
0. Brielle's piggy bank has all nickels and dimes. The total value of the money in her piggy bank is $\mathrm{\$}7$ If Brielle has 66 nickels, write and solve a linear equation to find the number of dimes she has.

Step 1 ：First, we need to find the slope (m), which is the change in rent divided by the change in square footage. The slope is calculated as $m=\frac{\mathrm{\$}1125-\mathrm{\$}975}{1100-800}=0.5$.

Step 2 ：Then, we can find the y-intercept (b) by substituting one of the given points into the equation and solving for b. We can use the point (800, $975). Substituting these values into the equation $y=mx+b$ gives us $\mathrm{\$}975=0.5\ast 800+b$. Solving for b gives us $b=\mathrm{\$}575$.

Step 3 ：Finally, we can use the equation to find the rent for a 1500 square foot office. Substituting $x=1500$ into the equation $y=0.5x+\mathrm{\$}575$ gives us $y=\mathrm{\$}1325$.

Step 4 ：Final Answer: The monthly rent for a 1500 square foot office is $\boxed{{\displaystyle \mathrm{\$}1325}}$.