Question

solve the system by substitution.

$-3x + 6y = 45$

$x = 8y + 9$

answer attempt 1 out of 2

$\big(\square, \square\big)$ submit answer

Explanation:

Step1: Substitute \( x = 8y + 9 \) into \( -3x + 6y = 45 \)

Substitute \( x \) in the first equation: \( -3(8y + 9) + 6y = 45 \)

Step2: Simplify the equation

Expand the left - hand side: \( -24y-27 + 6y=45 \)
Combine like terms: \( -18y-27 = 45 \)
Add 27 to both sides: \( -18y=45 + 27 \)
\( -18y=72 \)
Divide both sides by - 18: \( y=\frac{72}{-18}=-4 \)

Step3: Find the value of \( x \)

Substitute \( y = - 4 \) into \( x = 8y+9 \)
\( x=8\times(-4)+9=-32 + 9=-23 \)

Answer:

\((-23,-4)\)