$x + 2 + x + 4 + x + 6 + x + 8 =25760$
$x + 20 + x + x + x =25760$
$4x +20 = 25760$
$4x = 25760 - 20$
$4x = 25740$
$x = 25740 :4$
$x =6435$
$(6975-x+785) :4=859$
$6975 - x + 785 = 859 x 4$
$6975 - x + 785 = 3436$
$6975 - x = 3436 - 785$
$6975 - = 2651$
$x = 6975 - 2651$
$x = 4324$