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use the substitution method to solve the linear system.
1. 3x=9
-x+2y=9

3x/3 = 9/3
x = 3

-x(3)+2y = 9
-3+2y = 9
2y = 12
y = 6

is (3,6) correct?

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also, can you please tell me how to solve these?

use the linear combinations to solve the linear system:
2.x+y=3
x+2y=6

3. x+y=7
y=-2x+8

thanks

  • maths -

    Yes, on (3.6)

    2)
    x+y=3
    x+2y=6

    subtract the second equation from the first:

    x+y=3
    -(x+2y=6)
    or the result is -y=-3
    y=3
    then go back and solve for x.

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