Solve the system using substitution. x + y = 8 y = 3x a. (4, 12) b. (2, 6) c. (1/2, 3/2) d. (-4, -12)

Solve the system using substitution.
x + y = 8
y = 3x

a. (4, 12)
b. (2, 6)
c. (1/2, 3/2)
d. (-4, -12)

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  1. X+y=8
    y=3x

    You would want to substitute the y for the 3x
    x+3x=8

    You can now add the x with the 3x to get 4x
    4x=8

    Now divide the 4 on both side to solve for x
    x=2

    Now to solve for y just substitute the x for the 2
    y=3(2)

    Now multiply the 3 and the 2 to solve for y.
    y=6

    So your corrct answer is B:(2,6)

  2. The solution set for the system of linear equations [tex]x + y = 8[/tex] and [tex]y = 3x[/tex] is [tex]\boxed{\left\{{\left({{\mathbf{2,6}}}\right)}\right\}}[/tex].

    Further explanation:

    It is given that the system of linear equations are [tex]x + y = 8[/tex] and [tex]y = 3x[/tex].

    Consider the given equations as follows:

    [tex]x + y = 8\,\,\,[/tex]      ......(1)

    [tex]y = 3x\,\,\,[/tex]          ......(2)

    From equation (2), the value of [tex]y[/tex] in terms of [tex]x[/tex] is[tex]3x[/tex].

    Now, substitute [tex]3x[/tex] for [tex]y[/tex] in the equation (1) as follows:

    [tex]x + 3x = 8[/tex]

    The variable is eliminated in the above equation.

    Simplify the equation as follows:

    [tex]\begin{aligned}x + 3x&=8\\4x&=8\\x&=\frac{8}{4}\\x&=2\\\end{aligned}[/tex]

    Therefore, the value of [tex]x[/tex] is [tex]2[/tex].

    Substitute [tex]2[/tex] for [tex]x[/tex] in the equation (2) and obtain the value of [tex]y[/tex] as shown below.

    [tex]\begin{aligned}y&= 3\left( 2\right)\\&=6\\\end{aligned}[/tex]

    Therefore, the value of [tex]y[/tex] is [tex]6[/tex].

    Thus, the ordered pair for the given system of linear equation is [tex]\left({{\mathbf{2,6}}} \right)[/tex].

    Check whether the obtained solution [tex](2,6)[/tex] satisfies the given equations or not.

    Substitute [tex]2[/tex] for [tex]x[/tex] and [tex]6[/tex] for [tex]y[/tex] in the equation (1) and check the equation.

    [tex]\begin{aligned}2 + 6\mathop&_=^? 8\hfill \\\,\,\,\,\,\,\,8 &= 8\,\,\,\hfill\\\end{aligned}[/tex]             (True)

    The ordered pair [tex]\left({2,6}\right)[/tex] satisfies the equation (1).

    Substitute [tex]2[/tex] for [tex]x[/tex] and [tex]6[/tex] for [tex]y[/tex] in the equation (2) and check the equation.

    [tex]\begin{aligned}6\mathop&_= ^? \:3\left( 2 \right)\hfill\\6&= 6\,\,\,\,\,\,\,\,\,\,\,\,\hfill\\\end{aligned}[/tex]              (True)

    The ordered pair [tex]\left({2,6}\right)[/tex] satisfies the equation (2).

    Thus, the solution set for the system of linear equations [tex]x + y = 8[/tex] and [tex]y = 3x[/tex] is [tex]\boxed{\left\{{\left({{\mathbf{2,6}}}\right)}\right\}}[/tex].

    Learn more:

    1. Which classification best describes the following system of equations?

    2. Which polynomial is

    3. Write the subtraction fact two ways 10-3?

    Answer Details:

    Grade: Junior High School

    Subject: Mathematics

    Chapter: Linear equations

    Keywords: Substitution, linear equation, system of linear equations in two variables, variables, mathematics,[tex]x + y = 8[/tex] ,[tex]y = 3x[/tex] , solution set

  3. Okay sub equation 2 into equation 1:
    so it becomes 

    x + 3x = 8
    4x = 8
    x = 2

    then 2 + y = 8, therefore y = 6
    So the answer is B

  4. Option B that is (2,6) is correct

    Explanation:

    We have been given with system of equations

    [tex]X+Y=8[/tex] and [tex]Y=3X[/tex]

    Here, we will substitute the value of [tex]Y=3X[/tex] in [tex]X+Y=8[/tex]

    We will get [tex]X+3X=8[/tex]

    Further simplification we will get to [tex]4X=8[/tex]

    Hence, the value of [tex]X=2[/tex]

    And now, substituting the value [tex]X=2[/tex] in [tex]Y=3X[/tex] we will get [tex]Y=6[/tex].

    Therefore, option B is correct.

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