Question

solve using substitution.
8x + 9y = 9
x + 2y = 9
(\boxed{\quad}, \boxed{\quad})

Explanation:

Step1: Solve the second equation for x

From \( x + 2y = 9 \), we can express \( x \) as \( x = 9 - 2y \).

Step2: Substitute x into the first equation

Substitute \( x = 9 - 2y \) into \( 8x + 9y = 9 \):

$$
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$$

Step3: Solve for y

Subtract 72 from both sides:

$$ -7y = 9 - 72 = -63 $$

Divide both sides by -7:

$$ y = \frac{-63}{-7} = 9 $$

Step4: Substitute y back to find x

Substitute \( y = 9 \) into \( x = 9 - 2y \):

$$ x = 9 - 2(9) = 9 - 18 = -9 $$

Answer:

\((-9, 9)\)