In the question it is mentioned that,
The co–ordinates of its vertices are A $\left( 2,3 \right)$, B $\left( 4,-4 \right)$ and C $\left( 6,-7 \right)$
Then, co-ordinates of ΔA’B’C’ under reflection within the line y $=0.$
So, A’ = $\left( 2,-3 \right)$
B’ = $\left( 4,4 \right)$
C’ = $\left( 6,7 \right)$
Now, co-ordinates of ΔA”B”C” under reflection in the origin,
A” $=\left( -2,3 \right)$
B” $=\left( -4,-4 \right)$
C” $=\left( -6,-7 \right)$