Asked by Jay
Find k so that the line through (4, 1) and (k, 3) is
a. parallel to 8x+9y=18
y= -8/9x + 8/9
b. perpendicular to 3x+4y=8
y= -3/4x +2
I have solved both equation and found the slope, but I am not sure were to go from there. When I tried it the first time I got -17/2 for K. Is this right or did I mess up? The "K" is throwing me so please let me know what I did wrong. Thank you!
a. parallel to 8x+9y=18
y= -8/9x + 8/9
b. perpendicular to 3x+4y=8
y= -3/4x +2
I have solved both equation and found the slope, but I am not sure were to go from there. When I tried it the first time I got -17/2 for K. Is this right or did I mess up? The "K" is throwing me so please let me know what I did wrong. Thank you!
Answers
Answered by
Damon
a.
9 y = -8x + 18
y = -(8/9) x + 2
slope = -8/9
so
(3-1)/(k-4) = -8/9
2(9) = -8(k-4)
18 = -8k+32
8 k = 14
k = 7/4
-----------
check
-8/9 = ? (3-1)/(7/4 -4)
= 2/(7-16)/4 = 8/-9 sure enough
9 y = -8x + 18
y = -(8/9) x + 2
slope = -8/9
so
(3-1)/(k-4) = -8/9
2(9) = -8(k-4)
18 = -8k+32
8 k = 14
k = 7/4
-----------
check
-8/9 = ? (3-1)/(7/4 -4)
= 2/(7-16)/4 = 8/-9 sure enough
Answered by
Damon
now in b we get the slope first
yes, -3/4
so the slope we want is
-1/m = 4/3
now
4/3 = (3-1)/(k-4)
4 k- 16 = 6
4 k = 22
k = 11/2
yes, -3/4
so the slope we want is
-1/m = 4/3
now
4/3 = (3-1)/(k-4)
4 k- 16 = 6
4 k = 22
k = 11/2