Really simple questions

[jay_shark]

There is 4.75+3.5+10.5 =18.75 in the pot before it's your turn to act .

These are pot odds of 18.75/7 = 2.678:1 which means you need to win 1/(3.678) = 27.18% of the time to show a profit . Since you have a 31% equity against this hand , the call is a profitable one .

Suppose the button raised an amount X and knows that you have a 31% equity against his hand . The amount he should bet so that calling is neutral EV is :

If he bets x , then you're getting pot odds of (8.25+x)/(x-3.5) . We want (x-3.5)/(8.25 +x+x-3.5)=.31
(x-3.5)/(4.75 +2x)=0.31

Solve for x and you should get 13.08... which is the maximum amount you can call .