Miles is going to spend fewer hours bicycling this week than he did last year.
For perpendicular lines, m1m2 = -1 or m2 = -1/m1; where m1 and m2 are the slopes of the lines.
Here line 1 is 3x - 7y = 42
7y = 3x - 42
y = 3/7 x - 6; Hence m1 = 3/7
m2 = -1/(3/7) = -7/3
Required equation y - y1 = m2(x - x1)
y - (-8) = -7/3(x - (-3))
y + 8 = -7/3(x + 3)
y + 8 = -7/3 x - 7
y = -7/3 x - 7 - 8
y = -7/3 x - 15
Answer:

Step-by-step explanation:
First, add two to both sides to get
There are two ways to solve this from here
- Think about what power you would have to raise 9 to to get to 27.
= 3 and
. So, multiplying the powers (because it is a power to a power) you get
. This means that
or x =
. - Take the log of both sides.
This gives us 
250 miles on 8 gallons of fuel
means 250 miles were traveled on 8 gallons, so an average of 250mi/8gal = 31.25 mpg