Question

solve the system by substitution.

$x = y$
$4x + 9y = -39$

answer attempt 1 out of 3

(\square, \square) submit answer

Explanation:

Step1: Substitute \( x = y \) into the second equation

Since \( x = y \), we can replace \( x \) with \( y \) in the equation \( 4x + 9y = -39 \). This gives us \( 4y + 9y = -39 \).

Step2: Combine like terms

Combining the \( y \) terms, we have \( (4 + 9)y = -39 \), which simplifies to \( 13y = -39 \).

Step3: Solve for \( y \)

Divide both sides of the equation \( 13y = -39 \) by 13: \( y = \frac{-39}{13} = -3 \).

Step4: Find \( x \) using \( x = y \)

Since \( x = y \) and \( y = -3 \), then \( x = -3 \).

Answer:

\((-3, -3)\)