Bantu jawab dong guys no10 & 11

 10)  2x + 3y = 11     dikalikan 5 →  10x + 15y  =  55
        5x + 39 = 2y     dikalikan 2 →  10x  -  4y   = -78
                                                        ----------------------- -
                                                                   19 y = 133
                                                                        y = 7
       x + 3y   = 11
        2x + 3(7) = 11
                  2x = 11 - 21
                  2x = - 10
                    x = - 5
5x + y = 5 (-5) + 7
           = -25 + 7
           = - 18

11)  beras disingkat b
       gula disingkat   g
       3b + 2g = 46.000  dikalikan 4 → 12b + 8g   = 184.000
       4b + 5g = 87.000  dikalikan 3 →  12b +15g = 261.000
                                                          ----------------------------- -
                                                                   - 7g  = - 77.000
                                                                       g  =  11.000
3b + 2g             = 46.000
3b + 2(11.000)  = 46.000
                  3b   = 46.000 - 22.000
                    b   = 24.000 / 3
                    b   =  8.000

1b + 0,5g = 1(8.000) + 0,5(11.000)
                = 13.500

kembaliannya  =  20.000 - 13.500
                        =  Rp 6.500,-