两边乘以12得3(3x-1)+2(7-5x)=129x-3+14-10x=12x=1 两边乘以10得5(2x+1)-(7x-4)=010x+5-7x+4=03x=-9x=-3
=x/2-2x+2y²/3-3x/2+y²/3=-3x+y²当x=-1/4,y=-1/2得原式=3/4+1/4=1
两边乘以12得3(3x-1)+2(7-5x)=129x-3+14-10x=12x=1 两边乘以10得5(2x+1)-(7x-4)=010x+5-7x+4=03x=-9x=-3
=x/2-2x+2y²/3-3x/2+y²/3=-3x+y²当x=-1/4,y=-1/2得原式=3/4+1/4=1