HELP on algebra ?

Tutoring | Bookmark Us | FREE to Join! New User? Sign Up | Sign In | Help

Students Ask Questions--Tutors Answer
TutorAnswer.com

TutorsTeach.com

ask.

answer.

discover.

My Profile

Home > Accounting & Taxes > Open Questions

317584

Open Questions

HELP on algebra ?

How would you solve this problem?
What is the y-intercept of the linear function below in a table chart. Explain please. THank you
X Y
-1 -3
1 -1
3 1
4 2

Posted 225 day ago

Report Abuse

Find Interesting

Email to Friends

Bookmark

Subscribe to Answer Alert

Answers (4)

The equation of a linear function is: y=ax+b, where b is the y-intercept when x=0.
using two of the given x,y data, we get
A) 1=3a+b, (using third set of x,y data)
B) 2=4a+b, (using forth set of x,y data)
solving for a & b, we get:
a=1, and b=-2, so the y-intercept = -2.
Of course, any two pairs of x,y data will give the same result.

Posted 225 day ago

( 0 )

( 0 )

Report Abuse

math_fanatic

First, the equation of a line has the form y=mx + b where m is the slope and b is the y-intercept.
You want to find b but in order to do that you need to know what m, x, and y are.

You can use any of the points above as x and y once you find m in order to solve for b, so let's find m first.

The formula for the slope of a line is as follows:
m= (y1 - y2)/(x1 - x2)

Let's choose the first two set of coordinates to be our (x1, y1) and (x2, y2)
So we have (-1, -3) and (1, -1)
Plug it into the equation:

m = (-3 - (-1))/(-1-1) = (-3 + 1)/-2 = -2/-2 = 1

so the equation of the linear function in question has the form y = 1x + b
Now plug in any of the coordinates to solve for b. I'll choose (4, 2)

2 = 1*4 + b
2 = 4 + b

subtract 4 from both sides to get:
-2 = b

so the line intercepts the y-axis at y = -2
The value of x is always 0 on the y-axis thus the coordinates of the y-intercept are (0, -2)

Posted 225 day ago

( 0 )

( 0 )

Report Abuse

matherapist

use the data to determine the slope of the line. The slope is the change in y divided by the change in x for any 2 points. Thus slope = m = (-3--1)/(-1-1) = (-2)/(-2)=1

The equation of a straight line is y = mx +b where m is the slope and b is the y intercept so use and x,y cordinate in the data and substitute so using the pair 4,2 we have 2 = 4x1+b or b=-2 which is the y intercept

Posted 225 day ago

( 0 )

( 0 )

Report Abuse

Doctor Bob

You can find the y-intercept by looking at the graph and seeing which point crosses the y axis. This point will always have an x coordinate of zero. This is another way to find the y-intercept, if you know the equation, the y-intercept is the solution to the equation when x = 0.

If you plot the (x,y) ordered pairs (-1,-3), (1, -1), (3,1), and (4,2) you will get a straight line (linear function). Ask yourself, which point crosses the y axis while its coordinate x is zero. The point that accomplishes that is point (0,-2).

Posted 225 day ago

( 0 )

( 0 )

Report Abuse

Other Open Questions in Accounting & Taxes

» I DON'T HAVE A CLUE- GEOMETRY

» Microsoft Excel 2007

» History Question! Thanks!

» Cell analogy to a school!

» A four digit number

©2009 TutorAnswer.com, All rights reserved! • Contact us • Terms & Conditions • Privacy Policy •