Step-by-step explanation:
X=y-5
Now,
4x-y=4
4(y-5)-y=4
4y-20-y=4
3y=24
Y=8
Substituting the value of y
8-5=x
X=3
Perpendicular lines have slopes that are reciprocals and opposite signs. Reciprocal means to flip a fraction. If it is a whole number, put it over 1 and flip it. Then change the sign to its opposite.
You could also do -1 divided by the slope you want to be perpendicular to.
In this question, two things have been asked, but the funny thing is that the answer to both the questions can be reached following a single procedure. The information's that have already been provided in the question are:
Number of books Samantha has = 45
Number of books that can be packed in a box = 7
Number of boxes that can be packed with 7 books can be found by dividing the total number of books by the number of books in a box. also the remainder that will be left is actually the number of books that were left after packing the boxes.
Then
Number of boxes containing 7 books each = 45/7
= 6 3/7
So 6 boxes can be packed with 7 books each and 3 books will be left behind.