## HELP!!!! one year ago Help me graph the line through the point P having slope m. Find the coordinates of two other points on the line. 34. P(-3,-1), m=0.75

1. HELP!!!!

@Loser66 @SolomonZelman @zepdrix @Hero @Jaynator495

2. zepdrix

Since we're given a slope and a point, it's probably best to write the equation for our line in point slope form.

3. zepdrix

So here is what point-slope looks like:$\large\rm y-\color{orangered}{y_o}=m(x-\color{orangered}{x_o})$Where $$\large\rm (\color{orangered}{x_o},~\color{orangered}{y_o})$$ is the given point.

4. zepdrix

Plugging in our values gives us,$\large\rm y-\color{orangered}{(-3)}=0.75(x-\color{orangered}{(-1)})$Simplifies to,$\large\rm y+3=0.75(x+1)$

5. zepdrix

This will help us find other points on the line.

6. HELP!!!!

nice! Thanks for the clarification!

7. zepdrix

To graph it easily, we just need one more point. Then we can draw a line through the two points.

8. HELP!!!!

Yup I figured. I just got confused when it asked me to find another sets of points

9. zepdrix

Ahh woops! I plugged the numbers in backwards!! :O Notice I plugged the -3 into the y.

10. zepdrix

$\large\rm y+1=0.75(x+3)$My bad >.< Our point was this: $$\large\rm P(-3,-1)$$ It was NOT this $$\large\rm (-1,-3)$$ which is what I plugged in at the start.

11. zepdrix

So we need another point? Hmm... Let's plug in x=0 and see if we can come up with something.

12. zepdrix

$\large\rm y+1=0.75(0+3)$So we're currently working on finding this point: $$\large\rm (0,?)$$ We're choosing 0 for x, and we're going to solve this equation for y to see the corresponding coordinate value.

13. zepdrix

Understand how to solve for y in that setup? :o

14. HELP!!!!

Yuup! Also could you help me out with a word problem related to slope?

15. HELP!!!!

A ramp to provide handicapped people access to a certain building is to be constructed with a slope of 5%. If the entrance to the building is 3 ft above ground level, how long should the base of the ramp be?

16. zepdrix

$$\large\rm m=5\text{%}$$ So it would be nice if we could write this as an actual number, not a percentage. Do you remember how to convert it? :)

17. HELP!!!!

hmm is it out of 100? I have no clue

18. zepdrix

Yes, per cent means per 100. Think of the word century, which measures 100 years. So 5% means, 5 per 100. So we can write that as a fraction: $$\dfrac{5}{100}$$

19. HELP!!!!

so thats the slope?

20. zepdrix

$\large\rm m=\frac{5}{100}$Yes, that's the slope. Let's simplify it down. Both top and bottom are divisible by 5.

21. HELP!!!!

so 1/20

22. zepdrix

|dw:1443660767334:dw|

23. HELP!!!!

wOw nice drawing!

24. zepdrix

|dw:1443660878426:dw|

25. zepdrix

Do you remember your slope formula? Finding the slope of a line, given two points?

26. HELP!!!!

y2-y1/x2-x1 so x-0/3-0 =x/3?

27. HELP!!!!

ops nvm m=3/x

28. zepdrix

Mmm ok good! $\large\rm m=\frac{y_2-y_1}{x_2-x_1}=\frac{3-0}{x-0}$But recall that we actually KNOW the value of m, let's plug it in!$\large\rm \frac{1}{20}=\frac{3}{x}$And solve for x.

29. HELP!!!!

x=60!

30. zepdrix

yay good job \c:/ now the guy in the chair can safely get up the ramp

31. zepdrix

or down

32. HELP!!!!

Thanks for the major help! There needs to be more people like you

33. zepdrix

:3