How to find the height of a tree in cm. 5m and 4m equal how many cm

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

Plz hurry evaluate the expression a+b where a=8 and b=19

The scatterplot represents the total fee for hours renting a bike. the line of best fit for the data is y = 6.855x + 10.215. which table shows the correct residual values for the data set?