anonymous
  • anonymous
The objective is to solve system problems of equations by the addition method ( no multiplying required) how would you solve this : 2x+y=3 -2x+5y=-9 have solve for x and y to plot on graph.
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
jamiebookeater
  • jamiebookeater
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
2x + y = 3 -2x + 5y = -9 If you add straight down you get 6y = -6 divide by 6 and you get y = -1 Then you need to substitute the y = -1 into either one of the original equations. I will put it into the first one. 2x -1 = 3 add 1 to both sides 2x = 4 divide by two x = 2 So x = 2 and y = -1
anonymous
  • anonymous
How would you solve for x and y to plot on graph for this equation: 7x-y=12 -3y+7x+8 ?
anonymous
  • anonymous
Do you want to plot this on a graph to solve this?

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
yes, It's just like the previous question that I asked.
anonymous
  • anonymous
Check your second equation. there is something wrong with it. Then I will help you solve it.
anonymous
  • anonymous
-3=7x+8
anonymous
  • anonymous
Is there no y in that equation?
anonymous
  • anonymous
I'm sorry, it's -3y=7x+8
anonymous
  • anonymous
7x - y = 12 and -3y = 7x + 8 (First thing is to get the x's and y's on the same side.
anonymous
  • anonymous
7x - y = 12 -7x - 3y = 8 (I subtracted 7x from both sides)
anonymous
  • anonymous
7x - y = 12 -7x - 3y = 8 (Notice if you add straight down your x's are gone) -4y = 20 (Added the two equations together) y = -5 (Divide both sides by -4) Put y = -5 into 7x - y = 12 7x - (-5) = 12 7x + 5 = 12 7x = 7 x = 1 So... x = 1 and y = -5
anonymous
  • anonymous
same thing here: y=3x+13 2x=y-9 solve for x and y and plot on graph.
anonymous
  • anonymous
Put the x's and y's on the same side with the number on the other side... What do you get?
anonymous
  • anonymous
Is it 5x and 2y=4?
anonymous
  • anonymous
If you take y = 3x + 13 How do you get the 3x on the side with the y?
anonymous
  • anonymous
do you sub. 3x to move it?
anonymous
  • anonymous
Yes... so you get -3x + y = 13 Now the second equation 2x = y - 9 how do you get the y over with the 2x?
anonymous
  • anonymous
subtract y to move it
anonymous
  • anonymous
Yes.. so now you have 2x - y = -9 Now write both of those equations over each other.
anonymous
  • anonymous
-3x + y = 13 2x - y = -9 And you get this ... ok?
anonymous
  • anonymous
ok, then what do I do I know that I sub. and get -x=4 is this correct?
anonymous
  • anonymous
Well... you actually add but yes you get -x = 4 so to solve for x when x is negative you simply take the opposite of both sides. So the opposite of "negative x is positive x" and the opposite of "positive 4 is negative 4" x = -4
anonymous
  • anonymous
Now we are going to substitute x = - 4 into one of the equations. Let's use the y = 3x + 13 so.. y = 3(-4) + 13 y = -12 + 13 y = 1 So x = -4 and y = 1
anonymous
  • anonymous
last problem: 4x + 12 = -7y -y +12= 4x solve for x and y to plot on graph.
anonymous
  • anonymous
Get x's and y's on the same side with the number on the other. What would you get for 4x + 12 = -7y
anonymous
  • anonymous
4x-7y+12
anonymous
  • anonymous
Well you need an = sign in this problem... Bring the -7y over to the 4x and take the 12 to to the other side. What do you get?
anonymous
  • anonymous
I meant 4x-7y=12
anonymous
  • anonymous
If it is -7y on the right side you add 7y and it becomes + 7y on the left side. If it is + 12 on the left side you - 12 from both sides and it becomes -12 on the right side.
anonymous
  • anonymous
So you get 4x + 7y = -12 Try the 2nd equation -y + 12 = 4x
anonymous
  • anonymous
-4x+y=-12
anonymous
  • anonymous
Close.. You -4x which is correct, you - 12 which is correct.. but if you look at the 2nd equation is says "-y" on the left side so it needs to stay "-y" on the left side. -4x - y = -12 Now put those two over each other.. add... and tell me what you get.
anonymous
  • anonymous
y=-4
anonymous
  • anonymous
You should have gotten -6y = -24 Then you divide by -6 and you get y = 4 Now put y = 4 into one of the equations... Let's pick 4x + 12 = -7y
anonymous
  • anonymous
x=4
anonymous
  • anonymous
You should have gotten 4x + 12 = -7(4) 4x + 12 = -28 subtract 12 from both sides 4x = -40 divide by 4 x = -10 So the answers are x = -10 and y = 4
anonymous
  • anonymous
that can't be right because the puzzle I'm doing leaves me with the letter d which is x=4 and y=-4 to spell out a sudden debt payoff.
anonymous
  • anonymous
OK Let me do it again.
anonymous
  • anonymous
4x + 12 = -7y -y +12= 4x 4x + 7y = -12 -4x - y = -12 4x + 7y = -12 -4x - y = -12 6y = -24 y = -4 4x + 12 = -7(-4) 4x + 12 = 28 4x = 16 x = 4 You are correct x = 4, y = -4 Look thru my answer here... This is important you know how to do these because they are going to get harder on the next lesson and if you don't get this well, you won't get the next step. Study hard.... it pays off :-)
anonymous
  • anonymous
Thanks a lot I've got another sheet to do later maybe I'll get you again to help me. Is there a way I can ask for you personally?
anonymous
  • anonymous
Sure.. you can email me at amcbeth328@gmail.com
anonymous
  • anonymous
You were a great help. I'm not that great at math. I have a 62 average and my teacher told me that I have to get at least a 78 this 4 weeks or I will have to go to recovery school this summer.
anonymous
  • anonymous
I can tell you are weak... I would be glad to help you as long as you want to learn and not just want answers, because in the long run, you will get deeper and deeper into not getting it and it will hurt you in the long run.
anonymous
  • anonymous
I'm not looking for answers. I just don't understand how to do the problems sometimes and my teacher is so busy she doesn't have time to be one on one with to explain how to do them. I have always been weak in math but this year is really kicking me in the butt. I would go to tutoring but we don't have a car and no one in school will give me a ride home so therefore I'm kind of stuck trying to figure this stuff out on my own. It's been a long time since my parents were in school so they can't help me much.
anonymous
  • anonymous
Write me anytime.

Looking for something else?

Not the answer you are looking for? Search for more explanations.