Lauren drove her car 20 miles on 10 gallons and gasolin. At this rate, how many gallons qill she use on a 1,200 mile trip?
1 answer:
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Answer:
Step-by-step explanation:
Part A
We will use the slope intercept form of the line and then convert later.
Equation
y = mx + b is the general form
Givens
Two data points
(4,180)
(9,325)
Solution
325 = 9x + b
<u>180 = 4x + b</u> Subtract
145 = 5x Divide by 5
145/5 = 5x/5 Do the division
29 = x This represents the cost / day
180 = 4x + b Substitute x = 29 to find b
180 = 4*29 + b Combine
180 = 116 + b Subtract 116 from both sides.
180 - 116 = b
64 = b
Solution for y = mx + b
y = 29x + 64
In Standard form this is
- 29x + y = 64 But the first number must be plus
29x - y = - 64 <<<< Answer A
Part B
y = 29x + 64
f(x) = 29x + 64
Part C
The graph is shown below. Various points are filled in using y = 29x + 64. The y intercept is (0,64) which is labeled. Let x = 1 , 2, 3, 4, ... 10 (which is arbitrary). This may be more easily done on a spreadsheet if you know how to use one to make graphs.
