Question

$x - y = 9$
$y = x + 9$

Explanation:

Step1: Rearrange the first equation

Start with $x - y = 9$. Isolate $y$ by subtracting $x$ from both sides, then multiply by -1:
$-y = 9 - x$
$y = x - 9$

Step2: Compare with the second inequality

The second expression is $y < x + 9$. Substitute the rearranged $y$:
$x - 9 < x + 9$

Step3: Simplify the inequality

Subtract $x$ from both sides:
$-9 < 9$

Answer:

The inequality $-9 < 9$ is always true, meaning all values of $x$ and $y$ that satisfy $y = x - 9$ will also satisfy $y < x + 9$. The solution set is all pairs $(x, x-9)$ where $x$ is any real number.