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Hey. We're learning a new chapter in algebra now and I don't really understand it at all =(. I want to get ahead and figure it out before we have a test or quiz so help would be Greatly appreciated! I'm in ninth grade and doing Algebra. We're working on solving linear systems by graphing. If anyone can explain two of these problems step by step (literally) I would be SO happy and wish that I'd be able to give you a medal =)Ok here it goes. number 30. -3x+y=10 and the second one that goes to this is 7x+y=20 My question is what do you do step-by step and how do u graph it? Sorry I know this is REALLY confusing but I know someone out there can help me! Thank you sooo much in advance! =) (link)
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Hello. Well, hopefully you already know how to graph an equation in y=mx+b form. The "b" is the y-intercept (the point on the y-axis where the line touches). The "m" is the slope of the line (rise divided by run, or rise over run).
So the FIRST step is to convert the equations to y=mx+b form. This means that you need to solve the equations for "y". Here's how you do that.
-3x+y=10 This is the original equation.
+3x +3x Add 3x to both sides.
y=3x+10 This is your equation.
Remember, you tried to get "y" by itself, so you had to move the "x" to the other side. Now you need to do the same thing with the other equation.
7x+y=20 This is the original equation.
-7x -7x Subtract 7x from both sides.
y=-7x+20 This is your equation.
So your two new equations are y=3x+10 and y=-7x+20. Now you simply graph each equation.
To graph y=3x+10, you first find the y-intercept, which is 10 (remember the y=mx+b formula). So from the middle of the graph (the origin), go up 10 units and put a dot. From that dot, move up 3 more units AND move right 1 unit. Put another dot there and connect the 2 dots. That is your line. Make sure that the line goes on and does NOT end.
Now do the same thing to the other equation. Wherever both lines cross is your answer. It should be a point on the graph in (x,y) form.
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Rating: 5
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Thank you SOOOO much that was wonderful! lol I really appreciate it! =)
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