Use the substitution method to solve the system x=y−4

, x+8y=2
.(1 point)
Responses

infinite solutions
infinite solutions

(−31/3,2/3)
left parenthesis negative 3 Start Fraction 1 over 3 End Fraction comma Start Fraction 2 over 3 End Fraction right parenthesis

no solution
no solution

(2/3,−31/3)

1 answer

To solve the system of equations using the substitution method, we have the following equations:

  1. \( x = y - 4 \) (Equation 1)
  2. \( x + 8y = 2 \) (Equation 2)

Step 1: Substitute Equation 1 into Equation 2.

We can substitute \( x \) from Equation 1 into Equation 2:

\[ (y - 4) + 8y = 2 \]

Step 2: Simplify the equation.

Combine the terms:

\[ y - 4 + 8y = 2 \]

\[ 9y - 4 = 2 \]

Step 3: Solve for \( y \).

Add 4 to both sides:

\[ 9y = 6 \]

Now, divide by 9:

\[ y = \frac{6}{9} = \frac{2}{3} \]

Step 4: Substitute \( y \) back to find \( x \).

Now substitute \( y = \frac{2}{3} \) into Equation 1:

\[ x = \frac{2}{3} - 4 \]

Convert \( 4 \) to a fraction with a denominator of 3:

\[ x = \frac{2}{3} - \frac{12}{3} = \frac{2 - 12}{3} = \frac{-10}{3} \]

Step 5: Write the solution.

Thus, the solution to the system of equations is:

\[ \left( \frac{-10}{3}, \frac{2}{3} \right) \]

However, none of the provided answers align exactly with this solution. If we check the original answer choices:

  1. Infinite solutions
  2. \( \left( -\frac{31}{3}, \frac{2}{3} \right) \)
  3. No solution
  4. \( \left( \frac{2}{3}, -\frac{31}{3} \right) \)

None of these match the computed solution \( \left( \frac{-10}{3}, \frac{2}{3} \right) \).

Thus, if we strictly look at our solution, we conclude the following: The system has a unique solution, which is not represented in the options given.

In this case, it's important to be cautious with the matching of formats and always double-check interim steps for accuracy.

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