Find a solution to the following system of equations –5x + 2y = 9 3x + 5y = 7

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Find a solution to the following system of equations –5x + 2y = 9 3x + 5y = 7

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Doris 4 years 2021-08-11T06:23:05+00:00 1 Answers 20 views 0

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  1. thongdat2
    0
    2021-08-11T06:24:54+00:00
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    Answer: (-1, 2)

    Step-by-step explanation:

    Let’s start by solving for x in

    -5x+2y=9\\-5x+2y+-2y=9+-2y\\-5x=9+-2y\\\frac{-5x}{-5} =\frac{9+-2y}{-5} \\x=\frac{2}{5} y+\frac{-9}{5}

    We can now sub this value of x in 3x+5y=7 and solve

    3x+5y=7\\3(\frac{2}{5} y+\frac{-9}{5})+5y=7\\(3)(\frac{2}{5} y)+(3)(\frac{-9}{5})+5y=7\\\frac{6}{5} y+\frac{-27}{5}+5y=7\\\frac{6}{5} y+\frac{25}{5}y +\frac{-27}{5}=7\\\frac{31}{5} y+\frac{-27}{5}=7\\\frac{31}{5} y+\frac{-27}{5}+\frac{27}{5}=7+\frac{27}{5}\\\frac{31}{5} y=\frac{62}{5} \\\frac{\frac{31}{5} y}{\frac{31}{5}} =\frac{\frac{62}{5} }{\frac{31}{5}} \\y=2

    Now we can sub in 2 for y in one of the equations

    3x+5(2)=7\\3x+10=7\\3x+10-10=7-10\\3x=-3\\\frac{3x}{3} =\frac{-3}{3} \\x=-1

    x=-1 and y=2 giving us the point (-1, 2)

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )