Algebra 2 help......

[TsuScorpio]

Ye, i know what's a freshman doing taking a class like this? Just go along with it......

I need help with Solving Systems of linear equations by elimination and substitution.
Not the normal ones neither......the name of it is just system.......

[Spurs]

give us some problems lol

[toadsdaki]

give an example? xD I think I could help you if i saw an example, weird but w/e

or someone else smarter could help

[Nate1213]

Yeah im in Trig this year(#1 in my whole grade ftw xD) and we just refreshed on that. Give an example and im sure someone here can show you what to do.

[TsuScorpio]

{Y=2x-1
{2x + 6y = 11

solve by using Substitution and elimination.Coinciding, Paralell, or one answer. Consistent or Inconsistent. If coinciding what is the point where they intersect. Do not graph. And this is the easiest problem........... >.<

[toadsdaki]

y = 2x - 1
6y = 11 - 2x (get in terms of Y)

6y = 12x - 6 (multiple by 6)
6y = -2x + 11 (now they equal each other so....)

12x - 6 = -2x + 11 (solve from here)
+2x +6 +2x +6

14x = 17
divide by 14
x = 17/14

Now you have X, so go back to one of your equations and plug X in.

y = 2 (17/14) - 1
you will get
y = 10/7

There you go, you get x = 17/14 and y = 10/7... so (17/14 , 10/7)

Also, good idea is to plug x into the other equation so

6y = 11 - 2 (17/14)
and you will end up getting the same answer... voila... if anyone wants to double check the work


EDIT: Dang I don't know where I went wrong Cursed is smart? xD

[Cursed]

{y=2x-1
{y+1=2x -> {2x=11-6y
{y+1=11-6y
{y=10-6y
{7y=10
{y=10/7 -> {2x=y+1
{x=17/7

piece of cake, wait till calculus

[Nate1213]

Yeah really right now we're doing 5 variable 5 equation systems which still arent that hard but they take forever and piss me off xD (i have absolutely ZERO patience)

[toadsdaki]

{y=2x-1
{y+1=2x -> {2x=11-6y
{y+1=11-6y
{y=10-6y
{7y=10
{y=10/7 -> {2x=y+1
{x=17/7

piece of cake, wait till calculus

aha i think i found your mistake
you say
y=10/7 -> 2x=y+1
2x = 10/7 + 7/7 = 17/7
you forgot to divide by 2 duh
so x = 17/14 i was right
simple mistakes... those kill me on tests

[Cursed]

throw in some roots and a sin or 2 and id remember how to count again

[toadsdaki]

or a calculator xD

[TsuScorpio]

hey um wheres the rest of the problem lol

[Nate1213]

Y=2x-1
2x + 6y = 11

Here's what i'd do. I like to use Linear Equations(elimination) instead of substitution method because its easier for me.

Y=2x-1 ----> (-2x+y=-1) make it so both the variables are on the same side.
+(2x+6y=11) now they are both in the same form. you now add them together to get rid of one variable. = 7y=10

now you can solve for y by dividing both sides by seven.

Y=10/7

Then you put Y back into the original equation to solve for X

10/7 = 2x - 1 (add one to both sides)
17/7 = 2x (divide by two)

17/14 = X

and 10/7=2(17/14) -1
10/7= 34/14 -1
10/7= 17/7 -1
10/7= 10/7
so... its right

This system of equations is consistent (consistent means that a set of equations has at least one answer)

They are not parallel because they intersect.

They are not coinciding because there is not more than one answer.(i think thats what it means. correct me if i'm wrong)

So there is one answer. (thats what your other choice was right?)

And you put the X and Y that we solved for in as your point of intersection.

So your point of intersection is (17/14 , 10/7)

I think thats all you needed. Re-post if we missed anything.

[Spurs]

lol those were the days, its the complex derivatives that suck