Answers

2015-06-03T20:09:13+05:30
77x-8y-11=0 ⇒77x-8y=11....eqn.(1).
8x-7y-7=0   ⇒ 8x-7y=7.....eqn.(2)
LCM of 8 and 7 ( numerical coefficients of y)=56.
So we make Numeric Coefficient of y equal to 56 in both case.
77x-8y=11 ⇒ 539x - 56y=77.....(1) (multiplying all terms by 7) and
8x-7y=2 ⇒64x-56y=14.......(2)
subtracting eqn.(2) from (1) we get:
539x-56y-(64x-56y)=77-14.
or,539x-56y-64x+56y=59
or,475x=59.
or,x=59/475.
Substituting x as 59/475 in 77x-8y=11 we get
59/475*77-8y=11
or,8y=9.56(approx)-11
or,y=-0.18 (approx).
Ans:x=59/475 , y=-0.18.

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2015-06-03T22:26:46+05:30
77x - 8y = 11    *  7
 8x - 7y =7       *   8

539x - 56y = 77
64x - 56y = 56

475x        =   21

x  =  21/475

now substitute this in  any of this equation
8x - 7y = 7    or
77x - 8y =11



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