Write the equation of the line parallel to the
y-axis and 7 units to the left of the y-axis.
!

x=-7

Step-by-step explanation:

If a line is parallel to the y-axis, then it is vertical because the y-axis is vertical.

A vertical line is in the form of x=a number.

Since the line we are looking for is 7 units to the left of the y-axis, then the line is x=-7.  -7 is 7 units left of 0.

7 units right would have been x=7.

Step-by-step explanation:

A line parallel to y-axis is a vertical line.

A vertical line has an equation x = a, where a is any real number.

The line is 7 units to the left of the y-axis. Therefore  the equation of this line is x = -7 (look at the picture).

step-by-step explanation:

part a. the differences are decreasing, so we know the sequence is not arithmetic. the ratios are constant (=3/4), so we know the sequence is geometric.

part b. from part a, we know the common ratio is 3/4, so each term is 3/4 of the one before. the initial term is the number of gallons at h=1.

g[h] = (3/4)·g[h-1]

g[1] = 384 . . . . initial value required for a recursive definition

part c. the general formula for a geometric sequence is

a[n] = a[1]·r^(n-1)

we have a[1] = 384, r = 3/4, and the term number given by h. the formula that follows is

g[h] = 384·(3/4)^(h-1)

part d. filling in the value and doing the arithmetic, we have

g[12] = 384·(3/4)^11 ≈ 384·0.042235136 ≈ 16.2183 . . gallons

part e. each gallon is 4 quarts, so

16.2183 gal × 4 qt/gal = 64.8732 qt