SOLUTION: Could I possibly get some help on these questions. Whatever help I can get I would appreciate it. Find the slope of the line passing through the points (4,0) and (4,5) Find

Algebra ->  Graphs -> SOLUTION: Could I possibly get some help on these questions. Whatever help I can get I would appreciate it. Find the slope of the line passing through the points (4,0) and (4,5) Find       Log On


   

Question 84511: Could I possibly get some help on these questions. Whatever help I can get I would appreciate it.
Find the slope of the line passing through the points (4,0) and (4,5)
Find the slope passing through the points (-9,-4) and (0,-4).
Determine which two equations represent parallel lines.
a. y=5/3x+4 b. y=-3/5x-7 c. y=2x+8 d. y=2x-4.
I was thinking c and d would be parallel, but I would like to get that verified before I turn that in.
Write the equation of the line with slope -2 and y-intercept (0,0). Then graph the line.


Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Finding the slope


Slope of the line through the points (4, 0) and (4, 5)



Since you CANNOT divide by 0, this means that the slope of the line is undefined.


Answer: The slope of the line is undefined.





Solved by pluggable solver: Finding the slope


Slope of the line through the points (-9, -4) and (0, -4)



m+=+%28y%5B2%5D+-+%28y%5B1%5D%29%29%2F%28x%5B2%5D+-+%28x%5B1%5D%29%29


m+=+%28-4+-+%28-4%29%29%2F%280+-+%28-9%29%29


m+=+%28-4+%2B+4%29%2F%280+%2B+9%29


m+=+%280%29%2F%289%29


m+=+0



Answer: Slope is m+=+0





Any two parallel lines have equal slopes. Since c) and d) have equal slopes of 2, this means they are parallel.

Solved by pluggable solver: FIND a line by slope and one point

What we know about the line whose equation we are trying to find out:

  • it goes through point (0, 0)

  • it has a slope of -2



First, let's draw a diagram of the coordinate system with point (0, 0) plotted with a little blue dot:



Write this down: the formula for the equation, given point x%5B1%5D%2C+y%5B1%5D and intercept a, is

y=ax+%2B+%28y%5B1%5D-a%2Ax%5B1%5D%29 (see a paragraph below explaining why this formula is correct)

Given that a=-2, and system%28+x%5B1%5D+=+0%2C+y%5B1%5D+=+0+%29+, we have the equation of the line:

y=-2%2Ax+%2B+0

Explanation: Why did we use formula y=ax+%2B+%28y%5B1%5D+-+a%2Ax%5B1%5D%29 ? Explanation goes here. We are trying to find equation y=ax+b. The value of slope (a) is already given to us. We need to find b. If a point (x%5B1%5D, y%5B1%5D) lies on the line, it means that it satisfies the equation of the line. So, our equation holds for (x%5B1%5D, y%5B1%5D): y%5B1%5D+=+a%2Ax%5B1%5D%2Bb Here, we know a, x%5B1%5D, and y%5B1%5D, and do not know b. It is easy to find out: b=y%5B1%5D-a%2Ax%5B1%5D. So, then, the equation of the line is: +y=ax%2B%28y%5B1%5D-a%2Ax%5B1%5D%29+.

Here's the graph: