问题
解答题
化简或先化简后求值 ①x2+2x+3(x2-
②已知|a+3|+(b-
|
答案
①原式=x2+2x+3x2-2x
=4x2;
②∵|a+3|+(b-
)2=0,1 2
∴a+3=0,b-
=0,1 2
解得:a=-3,b=
,1 2
原式=2a2b+2ab2-2a2b+2-3ab2-2
=-ab2
=-(-3)×1 4
=
.3 4
化简或先化简后求值 ①x2+2x+3(x2-
②已知|a+3|+(b-
|
①原式=x2+2x+3x2-2x
=4x2;
②∵|a+3|+(b-
)2=0,1 2
∴a+3=0,b-
=0,1 2
解得:a=-3,b=
,1 2
原式=2a2b+2ab2-2a2b+2-3ab2-2
=-ab2
=-(-3)×1 4
=
.3 4