Question

1. \

$$\begin{cases} y = 2x \\\\ x + y = 9 \\end{cases}$$

Explanation:

Step1: Substitute $y=2x$ into second equation

$x + 2x = 9$

Step2: Combine like terms

$3x = 9$

Step3: Solve for $x$

$x = \frac{9}{3} = 3$

Step4: Find $y$ using $y=2x$

$y = 2\times3 = 6$

Answer:

$x=3$, $y=6$