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Question 445846: Tomorrow I have a test on slope intercept form, and solving system of equation. For slope intercept form, I know the formula is y=mx+b, and that m is slope and b is y intercept. I just don't understand how to graph it. An example is: Slope= -2, Y intercept= 1. The equation I came up with is Y= -2x+1. What number do I use for x, and how would I graph it.
For solving system of equations, I don't understand how to graph it either. For example: Y=-x and Y= x+2. How would you be able to put that on a graph.
I'm really sorry for how long that is, but it's super confusing for me. I had an A in math until this, and now I have a C. I'm hoping if I make a good grade on this test it will bring my grade up before final report cards. Thanks so much :)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Tomorrow I have a test on slope intercept form, and solving system of equation. For slope intercept form, I know the formula is y=mx+b, and that m is slope and b is y intercept. I just don't understand how to graph it. An example is: Slope= -2, Y intercept= 1. The equation I came up with is Y= -2x+1. What number do I use for x, and how would I graph it.
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You only need 2 points to determine the graph of a line.
Using your example: y = -2x+1
Let x = 0, then y = -2*0+1 = 1
That gives you the point (0,1)
So plot that point.
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Let x = 2, then y = -2*2+1 = -3
That gives you the point (2,-3)
So plot that point.
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Now draw a line thru those 2 points.
That is the graph you want.
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For solving system of equations, I don't understand how to graph it either. For example: Y=-x and Y= x+2. How would you be able to put that on a graph.
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Graph each line on the same x/y coordinate system.
If y = -x
Let x = 0, then y = 0 giving you point (0,0)
Let x = 2, then y = -2 giving you pont (2,-2)
Plot those points and draw the line.
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y = x+2
Let x = 0, then y = 2 giving you point (0,2)
Let x = 3, then y = 5 giving you point (3,5)
Plot those points and draw the line.
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To see the solution look for the point that
is on both of the lines. That is the solution
point.
If the lines are parallel, there is no solution.
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Hope that helps.
Cheers,
Stan H.
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