SOLUTION: 2.) the following table gives the number of miles (y) that a car can be driven on x gallons of gasoline. x | y 2 | 42 3 | 63 5 | 105 a.) e

Algebra ->  Graphs -> SOLUTION: 2.) the following table gives the number of miles (y) that a car can be driven on x gallons of gasoline. x | y 2 | 42 3 | 63 5 | 105 a.) e      Log On


   



Question 941698: 2.) the following table gives the number of miles (y) that a car can be driven on x gallons of gasoline.
x | y
2 | 42
3 | 63
5 | 105
a.) estimate how far the truck can go on 7 miles of gasoline
b.) how many gallons of gas are needed to travel a distance of 658 miles.
c.) how far can the truck go on a full tank if it holds 20 gallons of gasoline.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x | +y
2 | +42
3 | +63
5+ | +105
first find equation of the line passing through given points; take points (2,42) and (3,63)
Solved by pluggable solver: FIND EQUATION of straight line given 2 points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (2, 42) and (x2, y2) = (3, 63).
Slope a is a+=+%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%2863-42%29%2F%283-2%29+=+21.
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or 21%2A2+%2Bb+=+0. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=42-21%2A2+=+0.

y=(21)x + (0)

Your graph:




so, equation is:y=21x
a.) estimate how far the truck can go on 7 miles (here is probably gallons) of gasoline
y=21x if x=7
y=21%2A7
y=147 ...the truck can go 147 miles on 7 gallons of gasoline

b.) how many gallons of gas are needed to travel a distance of 658 miles.
y=21x if y=658
658=21x
658%2F21=x
31.33333333333333=x
x=31%281%2F3%29...to travel a distance of 658 miles 31%281%2F3%29 gallons of gas are needed


c.) how far can the truck go on a full tank if it holds 20 gallons of gasoline.

y=21x if x=20
y=21%2A20
y=420 ...the truck can go 420 miles on 20 gallons of gasoline