#3y=15-6x #
#y=(15-6x)/3#
#y=5-2x#
Put the value of #y# in #eq(2)#
#8x+2y=2#
#8x + 2(5-2x)=2#
#8x +10-4x=2#
#8x-4x=2-10#
#4x=-8#
#color(magenta)(x=-2#
Put #x=-2# in #eq1#
#3y=15-6x#
#3y= 15-6(-2)#
#3y = 15+12#
#3y= 27#
#y=27/3#
#color(magenta)(y=9#
#therefore# #color(red)(x=-2 and y=9#