A $60-$year$-$old man has a near point of$130$cmcm$,$making it impossible to read.

Part A

What power reading glasses would he need to focus on a newspaper held at a comfortable distance of$40$cmcm$?$

$-2\mathrm{.}9$DD$-1\mathrm{.}7$DD$+1\mathrm{.}7$DD$+2\mathrm{.}9$DD