Question 1038692
{{{A+B=30}}}
{{{A=30-B}}}
.
.
.
{{{AB>125}}}
Substituting,
{{{(30-B)B>125}}}
{{{30B-B^2>125}}}
{{{B^2-30B+125<0}}}
{{{(B-25)(B-5)<0}}}
Break up the number line into 3 regions,
{{{B<5}}}
{{{5<B<25}}}
{{{B>25}}}
Test the inequality in each region to see which satisfies the inequality.
{{{B<5}}}
{{{B=4}}
{{{(4-25)(4-5)<0}}}
{{{-21(-1)<0}}}
{{{21<0}}}
False.
{{{5<B<25}}}
{{{B=6}}
{{{(6-25)(6-5)<0}}}
{{{-19(1)<0}}}
{{{-19<0}}}
True.
{{{B>25}}}
{{{B=26}}
{{{(26-25)(26-5)<0}}}
{{{1(21)<0}}}
{{{21<0}}}
False.
So then,
{{{5<B<25}}}
which then leads to 
{{{5<30-A<25}}}
{{{-25<-A<-5}}}
{{{25<A<5}}}
or
{{{5<A<25}}}