Question

Answer 1

a, \(A=\sqrt{\left(a+3\right)^2}+\sqrt{\left(a-3\right)^2}=\left|a+3\right|+\left|a-3\right|=a+3+3-a=6\)

b, \(B=\sqrt{a-1+2\sqrt{a-1}+1}+\sqrt{a-1-2\sqrt{a-1}+1}\)

\(=\sqrt{\left(\sqrt{a-1}+1\right)^2}+\sqrt{\left(\sqrt{a-1}-1\right)^2}=\sqrt{a-1}+1+1-\sqrt{a-1}=2\)

Answer 2

Câu 8:

a: ĐKXĐ: -5x-10>=0

=>-5x>=10

hay x<=-2

b: ĐKXĐ: (x-1)(x-2)>=0

=>x>=2 hoặc x<=1

c: ĐKXĐ: x+3/5-x>=0

=>x+3/x-5<=0

=>-3<=x<5

d: ĐKXĐ: -(x-2)²>=0

=>(x-2)²<=0

hay x=2