Question 119286
Let's call the fraction,
{{{(A-1)/A}}}
"if 2 is subtracted from the numerator added to the denominator, the value of the fraction is 1/2"
{{{(A-1-2)/(A+2)=1/2}}}
{{{(A-3)/(A+2)=1/2}}}
{{{2(A-3)=(A+2)}}} Multiply both sides by 2(A+2). 
{{{2A-6=A+2}}}
{{{2A-A-6=2}}} Subtract A from both sides.
{{{A-6=2}}}
{{{A=2+6}}} Add 6 to both sides.
{{{A=8}}}
Original fraction
{{{(A-1)/A=7/8}}}
Check your answer
{{{(A-3)/(A+2)=1/2}}}
{{{(8-3)/(8+2)=1/2}}}
{{{5/10=1/2}}}
{{{1/2=1/2}}}
True statement.
Good answer.