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Question 514209: graphing linear equation using slope intercept form y=3x+4
Answer by xdragonfight(116)   (Show Source):
You can put this solution on YOUR website! Y=3X+4 THE Y INTERCEPT(b)=(0,4)
NOW SET Y=0 & SOLVE FOR X
0=3X+4
3X=-4
X=-4/3 THUS THIS POINT IS (-4/3,0)
NOW PLOT THESE 2 POINTS & DRAW THE LINE THROUGH THEM WITH A SLOPE (m) OF 3.
[THIS IS THE RED LINE].
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Y=-3X-4 HAS A Y INTERCEPT OF (0,-4)
NOW SET Y=0 & SOLVE FOR X
0=-3X-4
-3X=4
X=4/-3 THUS THIS POINT IS (-4/3,0)
NOW PLOT THESE 2 POINTS AND DRAW A LINE THROUGH THEM WITH A SLOPE (m) OF -4/3
[THIS IS THE GREEN LINE]
(graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = 3x +4 and y = -3x -4).
Answer by rapaljer(4420) (Show Source):
You can put this solution on YOUR website!
In contrast to the last problem that I posted about graphing straight lines, these two lines are given in SLOPE-INTERCEPT FORM (y=mx+b). In these cases, you can immediately identify the slope and the y-intercept of each line. The number term is always the y-intercept, and the coefficient of x is always the slope, which can be written as a fraction that we call the "RISE OVER THE RUN". Then you can graph them as follows:
y=3x-4
The y intercept is -4, and the slope m=3, which means .
Start by graphing the y-intercept by going DOWN 4 units on the y-axis. Then starting with your pencil on this point,GO UP 3 units, then go to the RIGHT 1 unit, and put the next point. Connect these two points with a line, and continue the line in both directions.
y=-3x-4
The y intercept is -4, and the slope m=-3, which means .
Start by graphing the y-intercept by going DOWN 4 units on the y-axis. Then starting with your pencil on this point,GO DOWN 3 units, then go to the RIGHT 1 unit, and put the next point. Connect these two points with a line, and continue the line in both directions.
If you want to see the point of intersection for these equations, then graph the two lines on the same graph, and see where the lines cross. This point is the point of intersection of the two lines.
For additional help on most AMU topic in algebra, see my website by clicking on my tutor name "rapaljer" anywhere in algebra.com. Look for the topic "Math in Living Color", choose a level of math, either Basic, Intermediate, or College Algebra, and look for the topic you need help with. If you can't find what you need, send me an Email, and maybe I can help you find the right page on my website!!!
R^2 at SCC
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