Answer :

ok sure!
first we have to find y

so...
lets start with the first one:

5x+y=2 (we cannot have two variables together so:
5x+y=2
   -y =-y  so.. now we have 5x= 2-y (but we must get y positive and by itself!) 
                                             -2    = -2
  so: now you have 
5x-2=-y but need a positive variable so multiply each side by a (-1) 
(-1) 5x-2=-y (-1) So..
-5x +2 =y so now we know Y!
therefore whenever you see why in the next problem insert in its place: -5x +2 
 
I hope it helps!! :) 
5x + y = 2      ⇒ 10x + 5y = 4
2x + 3y = 62  ⇒ 10x + 15y = 310
                                   -10y = -306
                                    -10      -10
                                         y = -30.6
                            5x - 30.6 = 2
                                 +30.6  +30.6
                                      5x = 32.6
                                       5        5
                                        x = 6.52
                                   (x, y) = (6.52, -30.6)