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SEE THE FOLLOWING EXAMPLE AND TRY.IF STILL IN DIFFICULTY PLEASE COME BACK
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\n" ); document.write( "I have working on this problem for some time but I am
\n" ); document.write( "still having a hard time working this one:
\n" ); document.write( "I am suppose to solve this system using elimination
\n" ); document.write( "method
\n" ); document.write( "10x+6y+z=7 (1)
\n" ); document.write( "5x-9y-2z=3 (2)
\n" ); document.write( "15x-12y+2z=-5 (3)
\n" ); document.write( "20x-21y=-2 (4)
\n" ); document.write( "Please show me how to work this problem from this
\n" ); document.write( "point.
\n" ); document.write( "Thank you
\n" ); document.write( "Good you have proceeded correctly and infact on the
\n" ); document.write( "way to solving the problem by your self..you only need
\n" ); document.write( "a little guidance on the path you should follow to
\n" ); document.write( "solve the problem..o.k. ..let us see you have added
\n" ); document.write( "equations 2 and 3 to get equation 3 ,which has
\n" ); document.write( "accomplished elimination of one unknown z . The basic
\n" ); document.write( "procedure is , if we start with 3 equations in 3
\n" ); document.write( "unknowns ,we try to eliminate one unknown taking one
\n" ); document.write( "pair of equations at a time to get 2 new equations in
\n" ); document.write( "2 unknowns only.Then we take those 2 new equations to
\n" ); document.write( "eliminate one another unknown to get one more new
\n" ); document.write( "equation , but this time with one unknown only.This we
\n" ); document.write( "can easily solve to find the unknown.Now , we travel
\n" ); document.write( "backwards along the same path as we travelled to find
\n" ); document.write( "the 2 other unknowns one after another by substituting
\n" ); document.write( "the known values every time.Let us illustrate the
\n" ); document.write( "procedure now with this example.Now that you have
\n" ); document.write( "already got one new equation 4 from 2 and 3 to
\n" ); document.write( "eliminate z., let us take equations 1 and 2 to
\n" ); document.write( "eliminate the same unknown z.For this we observe the
\n" ); document.write( "coefficients of z in the two equations which are 1 and
\n" ); document.write( "-2 respectively.So we multiply equation 1 with 2 and
\n" ); document.write( "add it to equation 2.
\n" ); document.write( "Eqn.1 * 2 gives us ...20x+12y+2z=14 .....(5)
\n" ); document.write( "Eqn.2 is .............5x-9y-2z = 3........(6)
\n" ); document.write( "Eqn.5 + Eqn.6 gives us .....25x+3y = 17....(7)
\n" ); document.write( "but from Eqn.4 we have
\n" ); document.write( ".....20x-21y=-2......(4)..proceeding on the same basis
\n" ); document.write( ",we eliminate y from these 2 equations.
\n" ); document.write( "Eqn.7 * 7 gives us .........175x+21y=119....(8)
\n" ); document.write( "Eqn.8 + Eqn.4 gives us .....195x=117 ..or x= 117/195 =
\n" ); document.write( "39/65 = 3/5.....now substitute this value of x in
\n" ); document.write( "eqn.4 to get y
\n" ); document.write( "y=(20*(3/5)+2)/21=14/21=2/3…….now substitute these
\n" ); document.write( "values of x and y in eqn.1 to get z.
\n" ); document.write( "z=(7-10*(3/5)-6*(2/3))=-3………….. As a check ,you can
\n" ); document.write( "substitute these values of x,y,and z in the 3 given
\n" ); document.write( "equations to
\n" ); document.write( "verify that your answer is correct. \n" ); document.write( "