What a fun day we had today! Slope was the name of the game! And if that wasn’t enough, WRITING EQUATIONS OF LINE!! I thought the fun would never end. Here are some notes about finding the slope and writing the equations of a line (which is benchmark 6, by the way). The homework was from the book, #13 page 124 #13-51 (odd).
Coming up:
- BM 6 on Monday, 10/1
Posting for points question:
Pick 2 points of your own and write the equation of the line. Be sure to show your slope, each step, and your final answer. You might want to work out your sample before you type it in.
37 Comments
September 26, 2007 at 10:32 pm
Points: (5,17) (-3, 1)
m=1-17/-3-5=
-16/-8
=2
y=mx+b
(1)=2(-3)+b
1=-6+b
7=b
y=2x+7
woot woot.
September 27, 2007 at 7:42 am
Slope!!!
m= y2-y1
x2- x1
ex1) points
(-4,1), (6,5)
6 = -3
-10 5
September 27, 2007 at 2:59 pm
Slope:
y2-y1/x2-x1
points:(2,2), (1,1)
2-1/2-1=1/1=1
OR the rate of change!!
(2,2),(1,1)
^_^__^_^
-1/-1=1
September 27, 2007 at 3:29 pm
(1,3)(2,4)
slope=4-3=1
2-1=1
m=1
y=mx+b
3=1(1)+b
2=b
y=1x+2
September 27, 2007 at 4:20 pm
(2, 7) (0, -3) y=mx + b
-3-7= -10
m= ————-= 5
0-2= -2
-3= 5(0)+b
-3=b
y=5x-3
September 27, 2007 at 6:35 pm
(1,3) (15,5)
m=5-3/5-1
2-4
=2
_______________________________________________
y=mx+b
5=2(15)+b
1=30+b
b=29
_______________________________________________
y=2x+29
September 27, 2007 at 6:38 pm
My bad, i messed up on the y=mx+b
5=2(15)+b
5=30+b
b=25
_________________________________________________
So its actually “y=2x+25″
September 30, 2007 at 2:03 pm
(6,2) (7,5)
m=y2-y1/x2-x1
5-2=3
7-6=1
m=3/1
y=3x+b
(6,2)
2=3(6)+b
2=18+b
-18 from both sides
-16=b
FINAL ANSWER
y=3x-16
September 30, 2007 at 8:59 pm
(2,3) (1,2)
2-3/1-2
-1/-1
1
3=(1)2+b
3=2+b
3-2=b
1=b
Final Equation
y=(1)x+1
October 1, 2007 at 11:04 am
(6,2) (3,4)
m=y2-y1/x2-x1
4-2=3
3-6=-3
m=3/-3
y=-1x+b
(3,6)
6=-1(3)+b
6=-3+b
6-(-3)=b
9=b
Final Equation
y=-1x+9
October 1, 2007 at 11:10 am
ohh what the heck? that cool looking smiley is supposed to be an 8
October 1, 2007 at 11:11 am
y=mx+b
points: (6, -2) (-3,
8-2=6
-3-6=-9
m=-2/3
-2=-2/3(6)+b
-2=-4+b
add 4 to both sides
b=2
Final-
y=-2/3x+2
October 1, 2007 at 4:07 pm
(0,2)(2,5) y=3/-2+2
y=mx +b
3/-2(slope)
(2,5)
5=3/-2(2)+b
5=3+b
-3 -3
2=b
October 1, 2007 at 4:22 pm
(1,7), (5,3)
3-7=-4
5-1=4
m=-1
3=-1(5)+b
3=-5+b
b=8
y=-1x+8
October 1, 2007 at 5:35 pm
slope is y=mx+b
ex.(0,3) (5,8)
y2-y1 all over x2-x1
y=mx+b
8-3
5-0
m=1
3=1(0)+b
3=0+b
-0 -0
3=b
y=1x+3
October 1, 2007 at 6:05 pm
(1,1)(2,2)
Steps:
1. Find the slope of the 2 coordinates
(y2-y1) over (x2-x1)
2-1=1 2-1=1
slope=1
2. Pick any coordinate to substitute x and y in the formula to find the y intercept = y=mx+b
1=1(1)+b
1=1+b
minus 1 to each side
0=b
Equation of the line = y =1x
October 1, 2007 at 7:08 pm
Points are (3, 4)(4, 3)
Slope: -1/1
1.) y=mx+b
2.) 3=-1/1(4)+b
3.) 3=-4+b
4.) 7=b
October 1, 2007 at 7:09 pm
Oh sorry, final answer is y=-4x+7
October 1, 2007 at 7:39 pm
(-3,2)(5,1)
1-2/5-(-3)
-1/8
or 1 over 8
October 1, 2007 at 7:39 pm
did i do that right?
October 1, 2007 at 8:22 pm
Points: (5,3),(20,13)
13-3/20-5=
=2/3
y=mx+b
(3)=2/3(5)+b
3=10/3+b
9=10+b
-1=b
y=2/3x+(-1)
October 1, 2007 at 8:33 pm
(2,3) (1,2)
2-3/1-2
-1/-1
1
3=(1)2+b
3=2+b
3-2=b
1=b
last equation
y=(1)x+1
October 1, 2007 at 8:46 pm
(4,2) (3,5)
5-2=3
3-4=-1
3/1
3
2=12+b
-12-12
-10=b
y=3x-10
October 1, 2007 at 10:23 pm
Slope is y=mx+b
ex.(0,3) (5,8)
y2-y1 all over x2-x1 y=mx+b
8-3 5-0
m=1
3=1(0)+b
3=0+b
-0 -0
3=b
y=1x+3
October 1, 2007 at 11:18 pm
(3,-5) (4,0)
y=mx+b
5/1=5=m
0=5(3)+b
0=15+b
b= -15
so therefore, y=5/1x -15
October 2, 2007 at 3:50 pm
(3,-2) (-5,1)
y=mx+b
m=1-(-2)/-5-3
m=-3/8
y=-3/8x+b
1=-3/8(-5)+b
1=15/8+b
8=15+8b
-7=8b
-7/8=b
y=-3/8x-7/8
I hope thats right man
October 2, 2007 at 3:55 pm
(5,-2) (7,3)
y=mx+b
-2-3= -5
5-7= -2
y=-5/2x+b
-2= – 5/2 (5) +b
2(-2)= (- 25/2 + b)2
-4= -25+b
+25 +25
21=b
y=-5/2+21
October 2, 2007 at 3:59 pm
(2,-1) (4,-5)
4-2=2
5-(-1)=6
6/2=3/1
-1=3(2)+b
-1=6+b
-7=b
y=3x-7
October 2, 2007 at 4:22 pm
(1,2)(3,4)
3-1=2
4-2=2
slope 2/2
y=2/2x + b
2=2/2(1) + b
2=2/2 + b
y= 2/2x + 3/4
October 2, 2007 at 5:08 pm
(0,9)(7,10)
10-9=1
7-0=7
y=mx+b
y=1/7x+b
10=(1/7)7+b
10=7/7+b
10=1+b
10-1=9
9=b
y=1/7x+9
October 2, 2007 at 9:43 pm
~equation of a line~
Y2-Y1
m=——–
X2-X1
(2,3) (3,4)
4-3 1
3-2 1= m=1
y=mx+b 3=1(2)+b
3=2+b
3/-2=b
________
Iy=x+3/-2 I
————–
October 3, 2007 at 6:23 pm
(2,4) (6,8)
-4, -4=0
2=0(4)+b
2=b
2=0(4)+2
IS THIS CORRECT?
October 3, 2007 at 9:47 pm
Rate of Change
(0,1) (2,2)
0+2=2
1+2=3
Slope=2/3
October 3, 2007 at 10:18 pm
(5,2) (6,4)
4-2=2
6-5=1
m=2/1=2
y=mx+b
y=2(x)+b
2=2(5)+b
2=10+b
subtract 10 from both sides
b=-8
y=2x-8
October 4, 2007 at 10:26 am
(4,5)(3,1)
1-5=-4
3-4=-1
1=(4/1)3+b
1=12+b
-12 -12
-11=b
y=4/1x-11
October 4, 2007 at 9:13 pm
(0,3) (5,6)
y=mx+b
6-3= 3
5-0= 5
y=3/5x+b
3= 3/5 (0) +b
3= b
y=3/5+3
October 8, 2007 at 9:36 pm
(5,2) (0,6) y=mx+b
6-2= 4 , 0-5=5
6=4/5(0)+b
0=b
y=4/5x+0
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