Help with writing equations.
The pictures below have the questions I need help with.
Answers
I'm sure you know how to find the slope of a line if you know 2 points
on it ... The slope is ...
(difference in y-values) / (difference in x-values) .
Right ?
OK. Each line in these tables is a point on the graph of the table.
Pick two points from the table, and you can get the slope of the line
from them.
The first table (Plan-A) has these points in it:
1 . . . . . $20.15
2 . . . . . $20.30
3 . . . . . $20.45
4 . . . . . $20.60
You want to find the equation of the line with these 4 points on it.
That means you need to find the slope and the intercept of the line.
Take any two points straight from the table. I'll use the first two:
1 . . . . . $20.15
2 . . . . . $20.30
There you have two points on the line: (1, 20.15) and (2, 20.30) .
The slope is (difference in 'y') / (difference in 'x').
Difference in 'y' = (20.30 - 20.15) = 0.15
Difference in 'x' = (2 - 1) = 1
Slope of the line = (0.15) / 1 = 0.15
(What that really means is 15 cents per minute on Plan-A.)
Now you know that the equation of the line is [ y = 0.15x + intercept ].
Can you think of a way to find the intercept ?
Remember ... every point in the table is on the line.
So why not just take one of these points in the table, put it into the part of the equation that you already have, and watch the intercept fall out ?
You could use any point at all from the table.
I'll use the 3rd one.
y = 0.15x + intercept
20.45 = 0.15(3) + intercept
20.45 = 0.45 + intercept
Subtract 0.45 from each side: 20.00 = intercept
The equation of the graph for Plan-A is Charge = 0.15(minutes) + $20.00
===============================
Plan-B:
First two points:
Difference in y-values = (8.00 - 6.50) = 1.50
Difference in x-values = (10 - 5) = 5
Slope of the line = (1.50) / (5) = .30 (30 cents per minute)
Intercept = 5.00
Charge = 0.3(minutes) + $5.00
======================================
Plan-C:
Slope = 4.50 / 10 = 0.45
Intercept = zero
=================================
Plan-D:
Slope = (16.50 - 11.00) / (30 - 20) = 5.5/10 = 0.55
Intercept = zero
In each plan, the intercept is the cost just to sign up, before you use
the phone, and then the slope is the cost for each minute of talking on it.
Related Questions
Find the surface area of the two following figures. Show all your work.
Which are zeros of the following polynomial? 6x 2 - 11x - 10 = 0
What is the ratio equivalent to 18:8
In order to maximize the chances that experimental groups represent the population of interest, researchers should conduct ________ and ________. blind sampling; random group assignment blind group assignment; random sampling random sampling; random group assignment blind group assignment; blind sampling
Answers
Answer:
0.02 (rational)
2 (rational)
Square root of 2 (irrational)
Square root 1/2 (irrational)
Step-by-step explanation:
Rational numbers are numbers that can be in form of a/b such that a and b are not zeros. In other words, a and b are integers ranging from 1 to infinity.
Conversely, irrational numbers are numbers that are endless and are non repeating digits after decimal point.
Thus, from the questions above;
Answers
Answer:the equation that represents the cost of your video rentals is y = 14 + 2(x - 10)
Step-by-step explanation:
Let x represent the number of video rentals that you made in a month.
Let y represent the total cost of x video rentals that you make in a month.
Your video membership cost $14 per month for 10 video rentals. Each additional video rental is $2. Therefore, the equation that represents the cost of your video rentals would be
y = 14 + 2(x - 10)
Where x - 10 is representing additional video rental above 10
Answers
Answers
Answers
Answer: the number of four point questions in the test is 10.
the number of five point questions in the test 8
Step-by-step explanation:
Let x represent the number of four point questions in the test.
Let y represent the number of five point questions in the test.
There are 18 questions on the test. It means that
x + y = 18
Each question is worth either four or five points. The total is 80 points. This means that
4x + 5y = 80 - - - - - - - - - - - - - -1
Substituting x = 18 - y into equation 1, it becomes
4(18 - y) + 5y = 80
72 - 4y + 5y = 80
- 4y + 5y = 80 - 72
y = 8
x = 18 - y = 18 - 8
x = 10