先化简再求值（x+1）2-x(2-x),其中x=2

更新时间2019-08-04 07:57:56

(x+1)^2-x(2-x)

=x^2+2x+1-2x+x^2

=2x^2+1

=2*2^2+1

=8+1

=9

(x+1)^2-x(2-x)

=x^2+2x+1-(2x-x^2)

=x^2+2x+1-2x+x^2

=2x^2+1

=2*2^2+1

=8+1

=9

解：

(x+1)²-x(2-x)

=x²+2x+1-2x+x²

=2x²+1

=2×2²+1

=8+1

=9

解：原式=x²+2x+1-2x+x²

=2x²+1

=2×2²+1

=9

 

（x+1）2-x(2-x),

2x+2-2x+x*x

=x*x+2

x=2

原式=2*2+2=6