Question 999696
1.{{{B=A+4}}}
2.{{{B^2-A^2=120}}}
Substituting,
{{{(A+4)^2-A^2=120}}}
{{{A^2+8A+16-A^2=120}}}
{{{8A=104}}}
{{{A=13}}}
Then,
{{{B=13+4}}}
{{{B=17}}}