Question

Rút gọn các biểu thức:

C = \(\sqrt{b^2\left(b-1\right)^2};\left(b< 0\right)\)

D = \(\sqrt{\dfrac{\left(x-2\right)^4}{\left(3-x\right)^2}}+\dfrac{x^2-1}{x-3};x< 3\)

Answer 1

`C=\sqrt{b^2(b-1)^2}`      `(b < 0)`

Vì `b < 0=>b < 1`

`=>C=|b|.|b-1|`

`=>C=-b(1-b)=b^2-b`

_________

`D=\sqrt{[(x-2)^4]/[(3-x)^2]}+[x^2-1]/[x-3]`     `(x < 3=>3-x > 0)`

`D=[(x-2)^2]/[3-x]-[x^2-1]/[3-x]`

`D=[x^2-4x+4-x^2+1]/[3-x]`

`D=[-4x+5]/[3-x]`