Okay so if the graphs are parallel they’re going to have the same slope. so for example, 2a has y=3x+4 and y=3x+7.. those would be parallel because they both have 3x (the slope). The lines will be perpendicular when the slopes are the opposite reciprocal of one another. So on 2e you have one slope as -1/3 and the other as 3. That would be perpendicular. The opposite reciprocal just means that it will be the opposite sign (positive or negative) and you will basically flip the numbers ( 3/1 turns into 1/3). You’ll know if they are neither because the slope won’t follow any of these patterns. Some of them you may have to do an extra step, like 2b you need to get Y by itself before you can compare slopes
18x-5=18x-6
-5=-6 this will never happen, so the equation has no solution. <span />
There would be about 1,283,792 scores below 640.
The 87th percentile means that 87% of the scores are below 640. All we need to do is multiply the total number of scores by 0.87 and we will have the number below 640.
16.6 is the answer. 16 is the whole number so u just divide 3 and 5 and get .6