陈向东

mjfanshome

For integers a and b, if (a^3-a^2-b)^1/2=7, what is the value of a?

(1) a^2-a= 12

(2) b^2-b=2

答案 B

请牛人指教

[此贴子已经被作者于2008-8-28 11:14:50编辑过]

stpearl

a^3-a^2-b=49;

from (1) (2) we have a=4 or a=-3 / b=4 or b=-3

or a(a^2-a)=49+b

12a=49+b

mjfanshome

按照你的解释 答案是C?