This is the online extension of our classroom this semester (2007 Fall Term) at the SVRSS. The content here is being created by real students in a real classroom. Enjoy learning from and with each other...

Thursday, September 27, 2007

Summary Of First Unit

The things i learned in this unit was:
The Algebracically way to solve things.
ex.
L1: y = 1/2x + 1
L2: y = -2x - 4

(1/2x = -2x - 5) 2
x = -4x - 10
(10)/-5 = (-5x)/-5
-2 = x

and since:
y = -2x - 4

we get:
y = -2 (-2) - 4
y = 4 - 4
y = 0
( -2 , 0 )

The Substitution Method:
L1: x - y = -1
L2: x + 2y = 8

L1: " "----------> x = (-1 + y)
L2: " "---------> ( -1 + y ) + 2y = 8
-1 + y + 2y = 8
-1 + 3y = 8
3y = 9
y = 3

Since y = 3 and since
x + 2y = 8

then x + 2 ( 3 ) = 8
x + 6 = 8
x = 2
the solution is ( 2 , 3 )

The elimination method is basically the same way excpt that you use addition or subtraction in the problem:
L1: 5x + y = 16
L2: 2x + 3y = 3

L1: " " ------>( 5x + y = 16 ) 3
L1: 15x + 3y = 48
ADD L2: 2x - 3y = 3

You get: 17x =51
x = 3

And since 5x + y = 16
5 ( 3 ) + y = 16
15 + y = 16
There fore: y = 1

The solution is ( 3 , 1 )

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