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Question 623677: Dear All,
I wish if you could help me understand below, please?
The problem says: Line X has a slope of 3. The line passes through Point X at (-2,-1) and also passes through Point Z., which has an x-coordinate of 0. What are the coordinates of Point Z?
So I guess that I have to substitute the given values in the formula m=Y2-y1 / X2-X1 (sorry I could not find the small 2s and 1s in my keyboard). So I got: 3= -1-y/-2-0 then 3= -1-y / -2 and after that I am stuck. I do not know how to find the Y value.
Many thanks for your help.
Ilda
Found 2 solutions by Alan3354, MathTherapy:
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Line X has a slope of 3. The line passes through Point X at (-2,-1) and also passes through Point Z., which has an x-coordinate of 0. What are the coordinates of Point Z?
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Step 1: Use the point and y = mx + b to find b, the y-intercept
-1 = 3*(-2) + b
b = 5
------
That makes the eqn of the line thru the point
y = 3x + 5
================
Sub 0 for x
--> y = 5
Point Z is (0,5)
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website! Dear All,
I wish if you could help me understand below, please?
The problem says: Line X has a slope of 3. The line passes through Point X at (-2,-1) and also passes through Point Z., which has an x-coordinate of 0. What are the coordinates of Point Z?
So I guess that I have to substitute the given values in the formula m=Y2-y1 / X2-X1 (sorry I could not find the small 2s and 1s in my keyboard). So I got: 3= -1-y/-2-0 then 3= -1-y / -2 and after that I am stuck. I do not know how to find the Y value.
Many thanks for your help.
Ilda
What you're trying to find is  , the 2nd y-coordinate of the line
What you have is: 
 ----- Cross-multiplying
Since = 5, then coordinate point of Z = ( , )
Note:
The fact that Z's x-coordinate is 0 signifies that Z is the y-intercept. Therefore, the general form of the equation of a line (y = mx + b) should be used to solve for b, which would give the y-coordinate of Z. This is much easier, but only because itw's given that Z's x-coordinate is 0.
Send comments and “thank-yous” to “D” at MathMadEzy@aol.com
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