# 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)

## This Post Has 8 Comments

1. NetherisIsTheQueen says:

X=2 because add the x value to get 4 and then divide

2. gedntrxAa says:

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

3. mjarrelljr says:

b

Step-by-step explanation:

x+3x=8

4x=8

x=8÷4

=2

y=3×2

=6

(x,y)=(2,6)

hopefully it works for you

4. GiaTeyy6536 says:

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

Further explanation:

It is given that the system of linear equations are $x + y = 8$ and $y = 3x$.

Consider the given equations as follows:

$x + y = 8\,\,\,$      ......(1)

$y = 3x\,\,\,$          ......(2)

From equation (2), the value of $y$ in terms of $x$ is$3x$.

Now, substitute $3x$ for $y$ in the equation (1) as follows:

$x + 3x = 8$

The variable is eliminated in the above equation.

Simplify the equation as follows:

\begin{aligned}x + 3x&=8\\4x&=8\\x&=\frac{8}{4}\\x&=2\\\end{aligned}

Therefore, the value of $x$ is $2$.

Substitute $2$ for $x$ in the equation (2) and obtain the value of $y$ as shown below.

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

Therefore, the value of $y$ is $6$.

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

Check whether the obtained solution $(2,6)$ satisfies the given equations or not.

Substitute $2$ for $x$ and $6$ for $y$ in the equation (1) and check the equation.

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

The ordered pair $\left({2,6}\right)$ satisfies the equation (1).

Substitute $2$ for $x$ and $6$ for $y$ in the equation (2) and check the equation.

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

The ordered pair $\left({2,6}\right)$ satisfies the equation (2).

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

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

2. Which polynomial is

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

Subject: Mathematics

Chapter: Linear equations

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

5. doggosbepis says:

Okay sub equation 2 into equation 1:
so it becomes

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

then 2 + y = 8, therefore y = 6

6. colton1788 says:

X+3x=8
x=8-3x is how far i could simplify

7. loraine4664 says:

Option B that is (2,6) is correct

Explanation:

We have been given with system of equations

$X+Y=8$ and $Y=3X$

Here, we will substitute the value of $Y=3X$ in $X+Y=8$

We will get $X+3X=8$

Further simplification we will get to $4X=8$

Hence, the value of $X=2$

And now, substituting the value $X=2$ in $Y=3X$ we will get $Y=6$.

Therefore, option B is correct.

8. Dogtes9667 says:

X=2 y=6  2+6=8 and 3 times 2 =6