You can find the slope either by just looking at the line or using the slope formula.
#1: The slope formula is:
Find two points and plug it into the formula
I will use (0, 2) and (1, -1)
(0, 2) = (x₁, y₁)
(1, -1) = (x₂, y₂)

[two negatives cancel each other out and become positive]

m = -3
#2: To find the slope without having to do the work, you use this:

Rise is the number of units you go up(+) or down(-) from each point
Run is the number of units you go to the right from each point
If we start at a defined/obvious point, like (0, 2), find the next point and see how many units it goes up or down and to the right. The next point is (1, -1), so from each point, you go down 3 units and to the right 1 unit. So your slope is -3/1 or -3. You can make sure the slope is right by looking at another point.
The area formula for a parallelogram is base*height=area. Make an equation. You know the area and the height, so plug that into the equation, and you get x*18=396. Solve for x by dividing 396 by 18 and you get 22. So, the base is 22cm.
If you would like to complete the factorization, you can do this using the following steps:
<span>4p^2 + 36p + 81 = (2p + 9) * (2p + 9) = (2p + 9)^2
</span>
The correct result would be 9.