8х + 5у = -7 — 7х + бу = — 4

Question

8х + 5у = -7
— 7х + бу = — 4

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Kim Cúc 4 years 2021-08-28T00:11:01+00:00 1 Answers 14 views 0

Answers ( )

  1. Sapo1
    0
    2021-08-28T00:12:27+00:00
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    Answer: x = -0.2651 and y = -0.9759

    Step-by-step explanation:

    Solution by substitution method

    8x+5y= -7

    -7x+6y= -4 = 7x-6y=4

    Suppose,

    8x+5y=-7→(1)

    7x-6y=4→(2)

    Taking equation (1), we have

    8x+5y= -7

    ⇒8x= -5y -7

    ⇒x= -5y-7 / 8 →(3)

    Putting x= -5y-7 / 8

    in equation (2), we get 7x-6y=4

    7(-5y-7/8)-6y=4

    ⇒-35y-49-48y=32

    ⇒-83y-49=32

    ⇒-83y=32+49

    ⇒-83y=81

    ⇒y= 81 / -83

    ⇒y= -0.9759→(4)

    Now, Putting y= -0.9759 in equation (3), we get

    x= -5y-7

    x= -5(-0.9759)-7/8

    ⇒x= 4.8795-7/8

    ⇒x= -2.1205/8

    ⇒x= -0.2651

    ∴x= -0.2651 and y = -0.9759

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