Year 8 Maths: Simultaneous Equations
I need to know and understand the procedure on how to solve a problem simultaneously.
Here is an easy one I got from trial and error:
(1) Y = X + 2
(2) Y = 3X - 2
I know that Y = 4 and X =2, I just need to know how to get the answer.
September 29, 2010
9 Comments • Newest first
[quote=Todesser]In this case you may ask your teacher, why he didn't teach you that and how to get the hang of it (if necessary).[/quote]
He didn't teach us because we had so many interruptions in maths class, "Missing half your math's term." he said. He's teaching us next term, week's time, but I want to start writing up my revision sheet.
@Maxxtro
Don't like it? Why click it? There's other threads on basilmarket, you know?
[quote=Todesser]I might be sterotyping now, but you got a lv.150 bishop, you may aswell spend your time learing stuff that will benifit you in your future. You got at least 5 more years of math ahead and your knownlegend seems already realy poor[/quote]
Trust me, I played my bishop when I had LOTS of time. Now I'm spending most of my time studying. I'm doing this for my maths exam at the end of the year, which is in five weeks. Our teacher has never taught us Simultaneous Equations so I'm trying to get a grip on it so I can write it on my revision sheet.
[quote=saddays]God man, you shouldn't have people do your work for you. Use substitution. People have pointed out how to do that with the examples you have been given.[/quote]
Trust me, they're not doing my work. It's one question out of a million I'm having trouble on. Now if you don't mind, scat.
Thanks for those trying to help. [:
[quote=x179496x]New problem:
(1) Y = -2X + 7
(2) 9 = 3X + Y[/quote]
Solve this by substitution.
(1) Y = -2X + 7
(2) 9 = 3X + Y
9 = 3X + (-2)X+7
9 = 3X -2X + 7
X=9-7=2
Y=9-3X=9-3*2=3
God man, you shouldn't have people do your work for you. Use substitution. People have pointed out how to do that with the examples you have been given.
Nevermind, I got it.
Substitution works best only for two equations with two unknowns or for a dummy system of equations.
To solve more than two equations simultaneously, i'd just write it in matrix form and use row operations to reduce it to reduced row-echelon form.
(the Gauss-Jordan method)
[quote=Todesser]Dude, I did this in the beginning of year 7 o.o[/quote]
Why 2/3? Isn't the answer 1.5, not .6?
So,
(1) Y = 3X - 2
(2) Y = -3X - 1
3X - 2 = -3X - 1
6X - 2 = - 1
6X = 1
X = 1/6
Y = 3 x 1/6 - 2
Y = 3/2?
This is so confusing. x.x
Thanks for your help.