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For Anyone Who's Good At Algebra!
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! =)
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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
you need to get it into "y=mx+b" form.
to do that, you must get rid of x (put it on the other side) so, you have to do the opposite of what x is.
-3x+y=10
+3x +3x
that leaves you with
y=3x+10
then, to graph it.
go UP 10. (it's positive)
put a point.
then, for your slope,
go up 3, to the right 1.
[since it's just 3, it changes to 3/1]
7x+y=20
-7x -7x
leaves you with
y=-7x+20
go UP 20.
put a point.
go up 7 (always go up)
then to the LEFT 1 (since it's negative)
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First of all, you just need a graphing calculator to do this. Next, you need to take each equation and solve it for y like this...
7x + y = 20
-7x -7x
so the equation becomes
y = -7x + 20
and
-3x + y = 10
+3x +3x
so the equation becomes
y = 3x + 10
Now comes the part with the calculator. Graph the first equation (y=-7x+20) into the Y1 slot on your calculator. (The Y1 slot comes up after you hit the "Y=" button at the top left). Then, graph the second equation (y=3x+10) into Y2. So your screen will say:
Y1=-7x+20
Y2=3x+10
Now hit the "window" button located to the right of the "Y=" button. The window will need to be changed from time to time in order to see where the two graphs intersect. Make the Xmin 0, the Xmax 10, the Ymin 0, the Ymax 20. When you are finished, select the "graph" button located at the top right of your calculator.
Your graph should have an "X" slanted toward the right. Hit "2nd" "Trace" on your calculater (the "2nd" button first, and then the "trace" button). Select #5 intersect. Press enter three times. At the bottom of the screen, it tells you where the two graphs intersect. In this case, it is (1,13). And that is your answer!
I hope this helped! Let me know if you need anything else!
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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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Alrighty!!! i deffinatly just did this like last night
1. put them both into y=mx + b form
2. graph both of the systems on graph paper on a coordinate plain(you know like the long 'y' line and the long 'x' line.)... the same coordinate plain too, so you should end up with 2 lines on the same plain.....
3. Wherever the lines hit eachother will be your anwser
Example lets say where they hit is over 2, up 5
Your anwser is (2,5)
I hope i helped i mean if your this far in algebra you should have already been taught how to graph things.... if not im realli sorry
Hope i helped
Askme247
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-3x+y=10 7x+y=20
+3x +3x
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y= 10+3x plug this equation in to the other one
y= 10+3 7x+10+3x=20
y= 13 10x+10=20
-10 -10
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10x=10
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10 10
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x=1 plug x in to the other equation
Sorry it is so hard to follow, it's really hard to show without arrows and oral explanation. If you have any questions just ask.
I hope I Helped
~Morgan
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