Omfg. Homework help, PL0X.

[Sandman53]

Graphing was always easy for me... Infact I laughed when the teacher was explaing y=x and he said when x = 4 than y = 4 and this girl in the class just did not understand why. The teacher was practically yelling at her, and I couldn't really blame him.

The only trouble I had, and still have, is with word problems. When messing with just numbers I can usually crunch it out. But eventually you get into math where you just have to remember about a billion different forumulas, and some formulas only work on certain equations and with certain equations you have to something just a little different...

Math is lame.

[hobolord]

hmm i dun rememeber this i think i was sleepin in class that day

[Ramstien]

The substitution one is piss easy. I can't do elimination though. I did learn, but i wasn't paying attention.

[Astro]

Y=3x-4
Y=2x+5

Find out the X by doing the following:

3x-4=2x+5

3x-2x=5+4

x=9

Now if you substitute the x for 9:

Y=3x-4 = 3(9)-4 = 23
Y=2x+5 = 2(9)+5 = 23

There you go.

[Sandman53]

The substitution one is piss easy. I can't do elimination though. I did learn, but i wasn't paying attention.

Elimation only works is you can get either same X or same Y. So for example

Y = 2X + 5
Y = 3X - 5
--------------------

(First you need to make the X's equal... the common numerator is 6 hence)

3Y = 6X + 15
2Y = 6X - 10
------------------------

(Now to elimante X we need to make either the top or bottom negative)

3Y = 6X + 15
-2Y = -6X + 10
-------------------------
Y = 25
(The math is simple, just add)

So knowing that (Y = 25) we plug why back in to either Equation

25 = 3X + 15
10 = 3X
X = 3/10

Simple...

[Ramstien]

Elimation only works is you can get either same X or same Y. So for example

Y = 2X + 5
Y = 3X - 5
--------------------

(First you need to make the X's equal... the common numerator is 6 hence)

3Y = 6X + 15
2Y = 6X - 10
------------------------

(Now to elimante X we need to make either the top or bottom negative)

3Y = 6X + 15
-2Y = -6X + 10
-------------------------
Y = 25
(The math is simple, just add)

So knowing that (Y = 25) we plug why back in to either Equation

25 = 3X + 15
10 = 3X
X = 3/10

Simple...

Hardly. If anything, i un-learned.

[Raiyne]

What the, how old are you guys? In Singapore we learnt this last year in our 8th Grade, 14 years old. o_O This year all our maths involves algebra lol...

K what you need to do everytime is to make x the subject, that is, to make it alone. First you just make one of the variables alone and substitute it into the other equation, so the equation will only have one variable then you can just bring the numbers over and solve it.

For example:

y = 2x + 5 - first equation (1)
y = 3x - 5 - second equation (2)

Sub (1) into (2)

2x + 5 = 3x - 5
Bring 2x from the left to the right, so it'll become -2X
5 = 3x - 2x - 5
5 = x - 5
Bring -5 to the left so when it moves over the '=' sign it will become +5 right?
10 = x - third equation (3)

Sub (3) into (1)

y = 2(10) - 5
y = 20 - 5
y = 15

Voila solved.

y=2x

and

y=3x-2

y = 2x
y = 3x - 2

Just substitute the first one into the second equation so you'll have
2x = 3x - 2
bring 2x over
0 = x - 2
bring 2 over
x = 2

Donez!

y=x

y=2x-4

y = x
y = 2x - 4

x = 2x - 4
0 = x - 4
x = 4

Have fun with algebra! lol...

[Jakuza]

What the, how old are you guys? In Singapore we learnt this last year in our 8th Grade, 14 years old. o_O This year all our maths involves algebra lol...

K what you need to do everytime is to make x the subject, that is, to make it alone. First you just make one of the variables alone and substitute it into the other equation, so the equation will only have one variable then you can just bring the numbers over and solve it.

For example:

y = 2x + 5 - first equation (1)
y = 3x - 5 - second equation (2)

Sub (1) into (2)

2x + 5 = 3x - 5
Bring 2x from the left to the right, so it'll become -2X
5 = 3x - 2x - 5
5 = x - 5
Bring -5 to the left so when it moves over the '=' sign it will become +5 right?
10 = x - third equation (3)

Sub (3) into (1)

y = 2(10) - 5
y = 20 - 5
y = 15

Voila solved.



y = 2x
y = 3x - 2

Just substitute the first one into the second equation so you'll have
2x = 3x - 2
bring 2x over
0 = x - 2
bring 2 over
x = 2

Donez!



y = x
y = 2x - 4

x = 2x - 4
0 = x - 4
x = 4

Have fun with algebra! lol...

9th grade, Algebra (H).