Answer :

Let:

[tex]\begin{gathered} P=(x1,y1)=(-3,4) \\ P^{\prime}=(x2,y2)=(4,0) \end{gathered}[/tex][tex]\begin{gathered} x1+a=x2 \\ -3+a=4 \\ so\colon \\ a=4+3 \\ a=7 \\ ---- \\ y1+b=y2 \\ 4+b=0 \\ b=-4 \end{gathered}[/tex]

Therefore:

[tex](x,y)\to(x+7,y-4)[/tex]