[填空题]
A woman can see clearly witdp.( m6 emykbju b3 l3zp4cy5;h her right eye only when obc bzkr1.dv; xih ,lt*9jects are between 45 $cm$ and 155 $cm$ away. Prescription bifocals should have what powers so that she can see distant objects clearly (upper part) and be able to read a book 25 $cm$ away (lower part) with her right eye? Assume that the glasses will be 2.0 $cm$ from the eye.
$P_1$ = D(upper part)
$P_2$ = D(lower part)
