问题
解答题
(1)(-1)-2+(π-23)0-(-
(2)已知:a+
(3)(9x3y2-6x2y+3xy2)÷(-3xy); (4)先化简再求值:(m+1)2-5(m+1)(m-1)+3(m-1)2,其中m=-
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答案
(1)(-1)-2+(π-23)0-(-
)-11 2
=1+1+2
=4;
(2)a2+
=(a+1 a2
)2-2=32-2=7;1 a
(3)(9x3y2-6x2y+3xy2)÷(-3xy)
=-3x2y+2x-y;
(4)(m+1)2-5(m+1)(m-1)+3(m-1)2,
=m2+2m+1-5m2+5+3m2-6m+3
=-m2-4m+9,
当m=-
时,原式=-1 2
+2+9=101 4
.3 4