Question 134677
You need two equations.

Let X be the number of 2pointers and Y be the number of 3 pointers
He made 320 goals.
{{{320 = X + Y}}}

He also scored 500 points
{{{500 =  2X + 3Y + 50 }}}

{{{450 = 2X + 3Y}}}

The problem now is the number of points is way too low. Something is hosed in your problem. If all the shots were 2 pointers, he still scores 640 that way. Which is  more than 450. 

Check your total. Then adjust the equations accordingly and solve