Substitution method for two linear equations with two unknowns

To solve the system of equations using substitution, follow these steps:

• The system of equations given is: $\begin{cases} x + y = 18 \\ y = 13 \end{cases}$
• Step 1: Extract the given value for $y$ from the second equation: $y = 13$.
• Step 2: Substitute $y = 13$ into the first equation: $x + 13 = 18$
• Step 3: Solve for $x$ by subtracting $13$ from both sides of the equation: $x = 18 - 13$
• Step 4: After the subtraction, we find: $x = 5$

Therefore, the solution to the problem is $x = 5$ and $y = 13$.

To solve this system of equations, we'll use the substitution method as follows:

• Step 1: Identify the given information.
  We have two equations: $\begin{cases} 2x + y = 9 \\ x = 5 \end{cases}$
• Step 2: Substitute $x = 5$ into the first equation.
  The equation becomes: $2(5) + y = 9$ which simplifies to: $10 + y = 9$
• Step 3: Solve for $y$.
  Subtract 10 from both sides: $y = 9 - 10$ $y = -1$
• Step 4: Verify the solution.
  Substituting $x = 5$ and $y = -1$ back into the first equation confirms the solution:
  $2(5) + (-1) = 10 - 1 = 9$

Both equations are satisfied with $x = 5$ and $y = -1$.

Therefore, the solution to the system of equations is $x = 5, y = -1$.

To solve this system using the substitution method, we'll follow these steps:

• Step 1: Solve the first equation for one variable.

• Step 2: Substitute this expression into the second equation.

• Step 3: Solve for the second variable.

• Step 4: Use the value of the second variable to find the first variable.

Step 1: Solve the first equation $x + y = 5$ for $y$.
We have: $y = 5 - x$.

Step 2: Substitute $y = 5 - x$ into the second equation $2x - 3y = -15$.
This gives us: $2x - 3(5 - x) = -15$.

Step 3: Simplify and solve for $x$:
$\begin{aligned} 2x - 15 + 3x &= -15 \\ 5x - 15 &= -15 \\ 5x &= 0 \\ x &= 0. \end{aligned}$

Step 4: Substitute $x = 0$ back into $y = 5 - x$ to find $y$.
$\begin{aligned} y &= 5 - 0 \\ y &= 5. \end{aligned}$

Thus, the solution to the system of equations is $x = 0$ and $y = 5$.

The correct answer from the list of choices is: $x = 0, y = 5$

Let's begin by solving the system of equations using the substitution method.

First, solve the second equation for $y$:

$3x + y = 8$

Solve for $y$:

$y = 8 - 3x$

Next, substitute this expression for $y$ in the first equation:

$-x - 2(8 - 3x) = 4$

Distribute the $-2$:

$-x - 16 + 6x = 4$

Combine like terms:

$5x - 16 = 4$

Add 16 to both sides:

$5x = 20$

Divide by 5:

$x = 4$

Now, substitute $x = 4$ back into $y = 8 - 3x$ to find $y$:

$y = 8 - 3(4)$

$y = 8 - 12$

$y = -4$

Therefore, the solution to the system of equations is $(x, y) = (4, -4)$.

Thus, the values of $x$ and $y$ are $x = 4$ and $y = -4$.

To solve this system of linear equations using the elimination method, we will follow these steps:

Step 1: Align the equations for elimination.

• Write the equations as they are given:

$x - y = 5$ (Equation 1)

$2x - 3y = 8$ (Equation 2)

Step 2: Eliminate one variable.

• Multiply Equation 1 by 2 to align the coefficient of $x$ with that in Equation 2:

$2(x - y) = 2 \times 5$

Thus, the transformed Equation 1 is:

$2x - 2y = 10$ (Equation 3)

• Subtract Equation 2 from Equation 3 to eliminate $x$:

$(2x - 2y) - (2x - 3y) = 10 - 8$

This simplifies to:

$y = 2$

Step 3: Solve for the other variable.

• Substitute $y = 2$ into Equation 1 to solve for $x$.

$x - 2 = 5$

Solve for $x$ by adding 2 to both sides:

$x = 7$

Therefore, the solution to the system of linear equations is $\mathbf{x = 7}$ and $\mathbf{y = 2}$.

This solution matches the choice:

$x = 7, y = 2$