Parallel have same slope
Perpendicular have opposite reciprocal slopes. Ex. 2/3 is slope of one line so the perpendicular line would have slope of -3/2.
Find slopes of these lines.
-4x-5y=-4
-4x+4 =5y
Divide by 5
Y= -4x/5 +4/5
Second line: 10x-8y=-1
10x+1=8y
Divide by 8
10x/8 +1/8 =y
Y= 5x/4 +1/8
So if you look at slope of line 1= -4/5 and line 2 it’s 5/4 so these both are perpendicular.
It would last 13.5 weeks because you would make a proportion:
12/16 = x/18 and then cross multiply. You would get 216=16x, then you have to divide both sides by 16 to get x = 13.5
Let s = northbound train
Then
2s = southbound train
:
Distance = time * speed
4s + 4(2s) = 600
:
4s + 8s = 600
:
12s = 600
:
s = 600/12
:
s = 50 mph is the northbound train
Then
2(50) = 100 mph is the southbound train
:
:
Check:
4(50) + 4(100) = 600
80 degrees. 145 = (4x+5) + (6x-10) = 10x-5... so 10x = 150, x = 15. LMN = 6x-10 = 6(15) - 10 = 80.
