Question

solve using substitution.
9x - 9y = 18
x + 2y = -19
(□, □)

Explanation:

Step1: Simplify the first equation

Divide the equation \(9x - 9y = 18\) by 9:
\(\frac{9x}{9}-\frac{9y}{9}=\frac{18}{9}\)
\(x - y = 2\)
Then, express \(x\) in terms of \(y\): \(x = y + 2\)

Step2: Substitute \(x = y + 2\) into the second equation

Substitute into \(x + 2y = -19\):
\((y + 2)+2y=-19\)
Combine like terms: \(y+2y + 2=-19\)
\(3y+2=-19\)
Subtract 2 from both sides: \(3y=-19 - 2=-21\)
Divide both sides by 3: \(y=\frac{-21}{3}=-7\)

Step3: Find the value of \(x\)

Substitute \(y = -7\) into \(x = y + 2\):
\(x=-7 + 2=-5\)

Answer:

\((-5, -7)\)