Question

x的平方+x分之1+x的二次方+3x+2分之1+x的平方+5+6x分之1+x的二次方+7x+12分之1

快，在线急等！！

Answer 1

=1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)
=1/x-1/(x+1)+1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/(x+3)-1/(x+4)
=1/x-1/(x+4)
=(x+4-x)/x(x+4)
=4/(x²+4x)