Question

Can someone help me with number 4,5 and 6?

Answer 1

4) You know slope-intercept form is y=mx+b. So using these two given points, you can find the slope! 

(-8,5)  (-3,10) [Use the y1-y2 over x1-x2 formula to solve for slope]

10 - 5         5
---------   = ----- = 1 
-3-(-8)         5

Hurray! You got a slope of one. Now substitute this back into your original equation:
y=mx+b --> y=1x+b 

Next, we find what our "b" is, or what our y-intercept is:
Using one of the previous points given, substitute them into the new equation:
[I used the point (-3, 10) ]

y=1x+b
10=1(-3)+b  SUBSTITUTE 
10=-3+b     MULTIPLY
10=-3+b
+3   +3    ADD
----------
13=b     SIMPLIFY 

So, now we have our y-intercept. Use this and plug it into the equation:
y=1x+b --> y=1x+13 

y=1x+13 is our final answer.



5) So for perpendicular lines, your slope will be the opposite reciprocal of the original slope. (Ex: Slope is 2, but perpendicular slope is -1/2) 

We have the equation y= 3x-1, so find the reciprocal slope! 
--> y=-1/3x-1 

Good! Now we take our given point, (9, -4) and plug it into the new equation:

y=-1/3x-1
-4=-1/3(9)+b   SUBSTITUTE and revert "-1" to "b", for we are trying to find the y-     -4=-3+b          intercept of our perpendicular equation. 
+3   +3            ADD
--------
-1=b    SIMPLIFY 

So, our final answer is y=-1/3x+(-1)

6) I don't know, sorry! :(