Question

rotations
find $a$ after $r_{90^{\circ}}(x,y) = (-y,x)$.
$a = (?, )$

Explanation:

Step1: Identify coordinates of A

From the graph, $A=(1, 2)$

Step2: Apply 90° rotation formula

Use $r_{90^\circ}(x,y)=(-y,x)$. Substitute $x=1, y=2$:
$A' = (-2, 1)$

Answer:

$A' = (-2, 1)$