To find out if they are parallel we need to see if the gradient is the same, to do this we need to get y in terms of x:
assuming the first equation is x+y+7=0
y=-x-7
and
y=x-3
The gradient is the coefficient of x (the number infront of x)
For equation 1 the gradient is -1, and for number 2 it is 1, therefore they are not parallel.
However to check if they are perpendicular we need to see if their gradients multiply to equal -1.
-1*1=-1 therefore they are perpendicular
This is a probablity question
there are 3 slots, 26 letters of the alphabet
so in the first slot, we have 26 possible letters
2nd slot, we have 25 possible letters (we used one for the first slot)
3rd slot, we have 24 possible letters, (we used 2 for first and 2nd slot)
so in total, we have 26*25*24 or 15600 different 3 letter initials with no repeated letters
The answer is in the photo which I attached below
Lets say gallon is G
and the bin is B
X is the amount needed to fill the bin
1/2G +x = 2/3B
so if we cut 1/2 G in half it gives you 1/3 and that will fill the whole bin so
1/2G + 1/4G =B
so the answer is
3/4 of a gallon