The solution of (3,13) means you need to create two lines that satisfy x = 3 and y = 13
The two lines can be anything as long as they give this solution
For example, if you wrote x + y = 16 (you know their values already)
Then write another y - x = 10
From here you have your equations, turn them into the f(x) form.
x + y = 16 can be turned into y = 16 - x which is f(x)=16-x
y-x = 10 can be turned into y = 10 + x which is g(x)=10 + x
This is the concept of algebra, to get the slope of the line we need to rewrite the equation in slope intercept form y=mx+c, where m=slope, c=y-intercept.
Therefore re-writing our expression in slope-intercept form we get:
7x-3y=10
-3y=-7x+10
y=7/3x-10/3
The slope=7/3
hence we conclude that the slope of the line perpendicular to this is -3/7
It could be -20.50 but not sure do u have answer choices
First divide 29.79 feet by 6

But since you can't plant only a fraction of a tree, you can plant a maximum of 4 trees per row.
Now there are ten rows so...
10×4 = 40
You can plant 40 trees at the maximum.