Use the substitution method to solve the system x=y−4 , x+8y=2 .(1 point) Responses (23,−313) left parenthesis Start Fraction 2 over 3 End Fraction comma negative 3 Start Fraction 1 over 3 End Fraction right parenthesis (−313,23) 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 infinite solutions

1 answer

To solve the system of equations using the substitution method, we start with the two equations provided:

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

First, we can substitute the expression for \( x \) from the first equation into the second equation.

Substituting \( x = y - 4 \) into the second equation:

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

Now, simplify the equation:

\[ y - 4 + 8y = 2 \] \[ 9y - 4 = 2 \]

Next, add 4 to both sides:

\[ 9y = 2 + 4 \] \[ 9y = 6 \]

Now, divide both sides by 9:

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

Now that we have \( y \), we can find \( x \) using the first equation:

\[ x = y - 4 \] \[ x = \frac{2}{3} - 4 \] \[ x = \frac{2}{3} - \frac{12}{3} = \frac{2 - 12}{3} = \frac{-10}{3} \]

So the solution to the system of equations is:

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

Now, let's see if this matches any of the given responses:

  • The responses were:
    • (23, −313)
    • \( \left( \frac{2}{3}, -3 \frac{1}{3} \right) \)
    • (−3 \frac{1}{3}, 23)
    • \( \left( -3 \frac{1}{3}, \frac{2}{3} \right) \)
    • no solution
    • infinite solutions

The correct answer is \( \left( -\frac{10}{3}, \frac{2}{3} \right) \) which does not match any of the provided responses directly. So there is no appropriate response from the options given.