若5x减4与2(x 2)的值互为相反数,则x等于
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根据题意得:2x-5+17-3(x-2)=0,去括号得:2x-5+17-3x+6=0,移项合并得:-x=-18,解得:x=18,则x2-x=324-18=306.
∵y=2x2+7x-1,y的值与4x+1的值相等,∴2x2+7x-1=4x+1,即2x2+3x-2=0,即(2x-1)(x-2)=0,解得x1=2,x2=12;∵y的值与x2-19的值互为相反数,∴2
∵x2+4x-5与2-2x是互为相反数,∴x2+4x-5+2-2x=0,∴x2+2x-3=0,∴(x-1)(x+3)=0,解得x=-3或x=1.故答案为-3或1.
∵代数式x2-x-2与2x-1的值互为相反数,∴x2-x-2+2x-1=0,∴x2+x-3=0,b2-4ac=1-4×1×(-3)=13>0,∴x=-b±b2-4ac2a=-1±132×1,∴x1=-
2x+5与9-3x互为相反数2x+5=-(9-3x)2x+5=-9+3xx=14x-2=12
(x+y-1)²与根号2x-y+4互为相反数则(x+y-1)²+√(2x-y+4)=0则x+y-1=02x-y+4=0两式相加,得3x+3=0,解得x=-1代入x+y-1=0,得y
已知│x-y+1│与x2+8x+16互为相反数,求x2+2xy+y2的值.x-y+1=0;(1)(x+4)=0;x=-4;y=-4+1=-3;∴x2+2xy+y2=(x+y)²=(-4-3)
∵|x-y+1|与x2+8x+16互为相反数,∴|x-y+1|与(x+4)2互为相反数,即|x-y+1|+(x+4)2=0,∴x-y+1=0,x+4=0,解得x=-4,y=-3.当x=-4,y=-3时
根据题意x²+8x-1=9-x²2x²+8x-10=0x²+4x-5=0(x+5)(x-1)=0x=-5或x=1即当x=-5或x=1时,代数式x2+8x-1与x
因为它们是相反数所以它们相加为0所以-2x+5=-9+3x解得x=5/14x-2=-23/14
若2x+1与4x-2x-5的值互为相反数,则x的值是?2x+1=-(4x-2x-5)x=1或者x=-2/3
第(1)问怎么是x=1/4时,还求x的值?(2)a与2b互为相反数,且a=4(2-x²)-2x,b=2x²-x+3,则4(2-x²)-2x+2(2x²-x+3)
∵2x2+1与4x2-2x-5互为相反数,∴2x2+1+4x2-2x-5=0,∴3x2-x-2=0,即(x-1)(3x+2)=0,x-1=0或3x+2=0,解得x1=1,x2=-23.
x等于1或负三分之二
x^2+y^2=(x-y)^2+2xy而xy=[(x+y)^2-(x-y)^2]/4=-25/4所以原式=25-25/2=25/2或者根据x+y=0,直接求出x,y这样更简单
设a是方程x²-4x+m²-1=0的根,-a是方程x²+4x+m+5=0的根∴a²-4a+m²-1=0a²-4a+m+5=0两个式子相减得到
(1)(x^2-6x-16)+(4+2x)=0x^2-4x-12=0(x+2)(x-6)=0x=-2,x=6(2)x^2-4x+13=x^2-2*2*x+2^2+9=(x-2)^2+9>=9>0
2x²+1+4x²-2x-5=06(x²-x/3-2/3)=0x²-x/3-2/3=0(x-1/6)^2-1/36-2/3=0(x-1/6)^2=25/36x-
49(x-2y-5)*2
(1)|x-y+1|≥0,x^2+8x+16=(x+4)^2≥0两者互为相反数,所以|x-y+1|=x^2+8x+16=0x-y+1=0,x+4=0,所以x=-4,y=-3x2+2xy+y2=(x+y