## math_crasher 3 years ago Can someone pls tell me whether the graphs of the lines will be collinear, parallel, or intersecting? y= 4x+1 y=4x-3

1. jim_thompson5910

What are the slopes of each line?

2. pitankar

intersecting

3. math_crasher

why?

4. jim_thompson5910

no, the lines aren't intersecting

5. math_crasher

I just need the explaination of the formula to tell whether or not it is parallel or intersecting and col linear

6. jim_thompson5910

What are the slopes of each line?

7. math_crasher

thats all it is given, theres a formula for solving but I don't know it.

8. jim_thompson5910

Hint: the equation y = mx+b has the slope m

9. jim_thompson5910

ex: y = 9x + 20 has the slope of 9

10. pitankar

sorry the lines are not intersecting. Extremely sorry, I made a mistake. They have same slopes, so they should be parallel.

11. math_crasher

I guess its four right? thats fine

12. jim_thompson5910

4 is the slope, yes

13. jim_thompson5910

since the slope is 4 for both of the lines, the lines are either parallel or collinear

14. jim_thompson5910

the two lines are collinear if and only if the two y-intercepts are the same

15. jim_thompson5910

otherwise, the two lines are parallel

16. math_crasher

ah ok

17. pitankar

one passes from y=-3 and other from y=1, so they are parallel(since slopes are same) but not co-linear.

18. math_crasher

so if its the same its parallel and what happens if its collinear?

19. jim_thompson5910

no, if the y-intercepts are the same, the lines are collinear if the y-intercepts are different, the lines are parallel both cases are true when the slopes are both equal

20. math_crasher

oh ok i see, so it is collinear right?

21. jim_thompson5910

what are the y-intercepts for both lines?

22. math_crasher

i need help finding the y intercepts pls

23. jim_thompson5910

y = mx+b b is the y-intercept ------------------------------ ex: for y = 2x+11 11 is the y-intercept ------------------------------ ex: y = 14x-13 which is the same as y = 14x + (-13) -13 is the y-intercept

24. math_crasher

ah i see

25. math_crasher

in this case the y intercepts are the same, which is 4x? And what do I do with the 1 and -3?

26. pitankar

to find Y=intercept, put x=0 in each equation. simple. Any point on y-axis is represented as x=0 and y=Y

27. jim_thompson5910

no, that's not the y-intercept

28. jim_thompson5910

y = 4x + 1, y intercept is 1

29. jim_thompson5910

look back up at my 2nd to last post

30. math_crasher

oh right then the y intercepts aren't the same

31. jim_thompson5910

so the lines are parallel

32. math_crasher

ah ok what will happen if its intersecting?

33. jim_thompson5910

if the slopes are different, then the lines will intersect

34. math_crasher

35. jim_thompson5910

if the slopes are the same and the y-intercepts are the same, then the two lines are collinear

36. math_crasher

ah coolio thanks