解2y+x/2=10——這個嗎?兩邊乘以2得：4y+x=20[(2x+y)(2x-y)+(x+y)²-2(2x²-xy)]=[(4x²-y²)+(x²+2xy+y²)-(4x²-2xy)]=(4x²+x²-4x²)+(-y²+y²)+(2xy+2xy)=x...???a?????+b?????=25??a+b=7?????a-b??a?????-b???????????????????????????a+b=7?????????(a+b)²=49??a²+2ab+b²=49??a²+b²=25??25+2ab=49??2ab=24??ab=12(a-b)²=a²-2ab+b²=25-2??12=1??a-b=1??a-b=-1??a-b=1???a²-b²=(a+b)(a-b)=7??1=7??a-b=-1???a²-b²=(a+b)(a-b)=-1??7=-7???? ???????????? (3x-1)?????-(x+2??????? a?????-b?????-2b-1??????(3x-1)²-(x+2)²=[(3x-1)-(x+2)][(3x-1)+(x+2)]=(3x-1-x-2)(3x-1+x+2)=(2x-3)(4x+1)a²-b²-2b-1=a²-(b²+2b+1)=a²-(b+1)²=(a-b-1)(a+b+1)