Question

Solve using substitution.
x = -9
-9x + 8y = 9
(_,_)

Answer 1

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

1. \( x = -9 \)
2. \( -9x + 8y = 9 \)

Since we already know \( x = -9 \), we can substitute this value into the second equation.

Substituting \( x \) in the second equation:

\[
-9(-9) + 8y = 9
\]

Calculating \( -9(-9) \):

\[
81 + 8y = 9
\]

Now, subtract 81 from both sides:

\[
8y = 9 - 81
\]

\[
8y = -72
\]

Next, divide both sides by 8:

\[
y = \frac{-72}{8} = -9
\]

Now we have the values of \( x \) and \( y \):

\[
x = -9, \quad y = -9
\]

So the solution to the system of equations is:

\[
(-9, -9)
\]