Question

3倍根号X平方-2X+1-根号X平方+4X+4 急

Answer 1

3√(x^2-2x+1)-√(x^2+4x+4)

=3|x-1|-|x+2|

={3(x-1)-(x+2)=2x-5,x>=1;

{3(1-x)-(x+2)=1-4x,-2