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PLEASE!!!!i need help on these 4:
*4y=15-3x
2y=3x+21

*4x=5y-14
y=-6x-9

*5x=4y-30
2x=3y=-12

*2/3y=10+4x
5x=1/3y-8

use linear combinations to solve the system of linear equations

thank you!!!

  • math -

    4y=15-3x
    2y=3x+21

    4y=15-3x Divide with 2
    2y=(15/2)-(3/2)x

    2y=(15/2)-(3/2)x=3x+21

    (15/2)-21=3x+(3/2)x

    (15/2)-(42/2)=(6/2)x(3/2)x
    -(27/2)=(9/2)x Multiply with 2
    -27=9x Divide with 9
    x= -3
    2y=3x+21
    2y=3*(-3)+21
    2y= -9+21
    2y= 12 Divide with 2
    y=6

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