Tuesday, March 29, 2011

Solve the following simultaneous linear equations: (x-2)/5 = (1-y)/4 and 26x+3y+4=0

I agree with justaguide, the answer is x = -1/2 and y =
3


The step for solving the problem in my way
is:


We have two equations:


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


(2) 26x + 3y + 4 =
0


Step #1: Process the (1)
equation:


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


=> (x-2)/5 =
(1-y)/4


=> 4(x-2) =
5(1-y)


=> 4x - 8 = 5 -
5y


=> 4x + 5y -8 - 5 =
0


=> 4x + 5y - 13 =
0



Gime Times 3 to (1) => 3 (4x+5y-13)
=0


=> 12x + 15y - 39 = 0
................(1*)


Give Times 5 to (2) => 5 (26x
+3y + 4) = 0


=> 130x + 15y + 20 = 0
 ......(2*)



(1*) and
(2*)


12x + 15y - 39 = 0


130x +
15y + 20 = 0
 -


__________________


-118 x -
59 = 0  => - 118 x = 59


=> x = 59/-118 =
-1/2


Substitude x = -1/2 to either (1) or
(2)


Here I choose to substitute x = -1/2 to
(1)


=> 4x + 5y - 13 =
0


=> 4(-1/2) + 5y - 13 =
0


=> -2 + 5y - 13 =
0


=>  5y - 15 =
0


=>  5y = 15


=>
 y = 15/5 = 3


Thus, the answer is x = -1/2 & y =
3

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