题目内容
(-4)+(-3)+(+4)+(+3)
(-198)×+
3×27-6×26
(x+y+z)(x-y+z)(x+y-z)(x-y-z)
(3a-5b+2c)(-3a+5b+2c)
(-5)-(+3)+(-9)-(-7)
-23÷(-3)2×(-5)3÷[-(-2)]3
×5
+6/(a2-9)