Question

Tìm điề kiện xác định của bt :A=\(\sqrt{x+1}+\sqrt{4-2x}\)

b,Chứng minh rằng :B=\(\frac{1}{3}\sqrt{27}+\frac{1}{2+\sqrt{3}}\)là số nguyên

HELP ME!!!

Answer 1

a, A=15√x−11x+2√x−3+3√x−21−√x−2√x+3√x+3A=15x−11x+2x−3+3x−21−x−2x+3x+3

=15√x−11x−√x+3√x−3−3√x−2√x−1−2√x+3√x+3=15x−11x−x+3x−3−3x−2x−1−2x+3x+3

=15√x−11√x(√x−1)+3(√x−1)−3√x−2√x−1−2√x+3√x+3=15x−11x(x−1)+3(x−1)−3x−2x−1−2x+3x+3

=15√x−11(√x−1)(√x+3)−3√x−2√x−1−2√x+3√x+3=15x−11(x−1)(x+3)−3x−2x−1−2x+3x+3

=15√x−11−(3√x−2)(√x+3)−(2√x+3)(√x−1)(√x−1)(√x+3)=15x−11−(3x−2)(x+3)−(2x+3)(x−1)(x−1)(x+3)

=15√x−11−(3x+9√x−2√x−6)−(2x−2√x+3√x−3)(√x−1)(√x+3)=15x−11−(3x+9x−2x−6)−(2x−2x+3x−3)(x−1)(x+3)

=15√x−11−3x−9√x+2√x+6−2x+2√x−3√x+3(√x−1)(√x+3)=15x−11−3x−9x+2x+6−2x+2x−3x+3(x−1)(x+3)

=7√x−5x−8(√x−1)(√x+3)