问题
填空题
如果2x2+1与4x2-2x-5互为相反数,则x的值为______.
答案
∵2x2+1与4x2-2x-5互为相反数,
∴2x2+1+4x2-2x-5=0,
⇒3x2-x-2=0,
∴(x-1)(3x+2)=0,
解得x1=1,x2=-
.2 3
如果2x2+1与4x2-2x-5互为相反数,则x的值为______.
∵2x2+1与4x2-2x-5互为相反数,
∴2x2+1+4x2-2x-5=0,
⇒3x2-x-2=0,
∴(x-1)(3x+2)=0,
解得x1=1,x2=-
.2 3