algebra ?? and pionte slope form.... (thanks mathgirl....)?

Question

in 2001 there were 6688 electric powered vehicles in use in the US. in 1998 only 4760 electric vehicles were being used...

1. assume that the relationship between time, x, and # of electric powered vehicles, y, is linear. write an equation in slope - intercept form describing this relationship. use ordered pairs of the form (years past 1998, # of vehicles) equation in slope intecept form...

2.use this equation to predict the # of EP vehicles in use in 2007

Answer 1

Step 1. Find the slope...
The slope formula is the change in y-value divided by the change in x-value.
The change in y is 6688-4760
The change in x is 2001-1998
Find those two results and divide. That is your slope.

Step 2.Fill the slope and a point into the point-slope formula...
y=mx+b

The number you found for the slope...that's m. Fill it in.
Then choose either one of the points (2001,6688) or (1998,4760) it doesn't matter, your choice. The first number (the year) is x, the second number (# of cars) is y. Fill those into the formula. The only missing number is b. Solve for b.

Step 3. Solve for Question 2
y=mx+b

You know m from part 1. Fill it in.
You know b from part 2 Fill it in.
You know x...it's the year you're interested in 2007 (from the problem) Fill it in.
There's only one missing number...Solve for y. That's the number of cars expected in 2007.

Good Luck

Answer 2

point slope: y-yo=m(x-xo) where yo and xo are starting values and m is the slope

@1998 x=0 y=4760
@2001 x=3 y=6688

To find the slope m, divide the left side by the right side and get
(y-yo)/(x-xo)=m
(6688-4760)/(3-0)=m=(1928/3)=642.67

so the equation would be
y-4760=642.67(x-0)

in slope-intercept, solve for y
y=642.67x+4760

for 2007 x=9
y=642.67(9)+4760=10,544 cars

Answer 3

Your numbers (5 and -2) are the standards on the graph: x and y. same with -sixteen and four. the 1st set is x1, y1 and the 2d set is x2, y2. subtract y2-y1 divide by using x2-x1. this provides you with the slope.