Question 371842
1.{{{A+B=20}}}
.
.
I'm assuming you mean the difference of their squares.
2.{{{A^2-B^2=80}}}
From eq. 1,
{{{A=20-B}}}
{{{A^2=400-40B+B^2}}}
Substitute into eq. 2,
{{{400-40B+B^2-B^2=80}}}
{{{400-40B=80}}}
{{{40B=320}}}
{{{highlight(B=8)}}}
Then from eq. 1,
{{{A=20-8}}}
{{{highlight(A=12)}}}