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Need help! solve by elimination method?

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-4x-7y= -10 and 7x+6y=5, answer is (-1, 2). i don't want simple answer, please show ste by step answer.

i will select best answer and you will get 10 points.
asked Dec 25, 2012 in GEOMETRY by futai Scholar

1 Answer

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Given equations are

-4x-7y=-10------------(1)

7x+6y=5---------------(2)

Now eliminate the x

Multiply the equation (1) by 7

(-4x-7y)*7=-10*7

-28x-49y=-70----------(3)

Multiply the equation (2) by 4

(7x+6y)*4=5*4

28x+24y=20--------(4)

Adding the equations (3) and (4)

-28x-49y=-70

28x+24y=20

-------------------

      -25y=-50

y=50/25

y=2

Now substitute y value in equation (2)

7x+6(2)=5

7x+12=5

7x=5-12

7x=-7

x=-7/7

x=-1

The values of x and y are -1 and 2.
answered Dec 25, 2012 by friend Mentor

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