\(100-3\times\left(y+8\right)=1.\)

\(3\times\left(y+8\right)=99\)

y+8 = 33

y = 25

84 - 4 x ( 2y + 1 ) = 4

4 x ( 2y + 1 ) = 80

2y + 1 = 20

2y = 19

y = 19/2

Xét A-B=5-\(\sqrt{10}\)(2/3+1)= 5-\(\frac{5\sqrt{10}}{3}\)=5(1-\(\frac{\sqrt{10}}{3}\)) < 0

Vậy A<B

\(2\sqrt{10}=\sqrt{4\cdot10}=\sqrt{40}>\sqrt{36}=6\Rightarrow2\sqrt{10}>6\)

\(\Rightarrow15-2\sqrt{10}< 15-6=9\Rightarrow\frac{15-2\sqrt{10}}{3}< \frac{9}{3}=3\)mà \(3=\sqrt{9}< \sqrt{10}\Rightarrow\frac{15-2\sqrt{10}}{3}< \sqrt{10}\)

=\(\frac{1+\sqrt{3}}{2}\)

Hk tốt

\(\sin\)\(30^o+\sin60^o=\sin90^o\)

Đề bài là rút gọn A hả bạn?  Đkxđ : a > 0 
\(A=\left(\frac{1+a\sqrt{a}}{1+\sqrt{a}}-\sqrt{a}\right)\)\(.\left(\frac{1+\sqrt{a}}{1-a}\right)^2\) \(=\frac{1+a\sqrt{a}-\sqrt{a}\left(1+\sqrt{a}\right)}{1+\sqrt{a}}\)\(.\left(\frac{1+\sqrt{a}}{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)}\right)^2\) \(=\frac{1+a\sqrt{a}-\sqrt{a}-a}{1+\sqrt{a}}\)\(.\left(\frac{1}{1-\sqrt{a}}\right)^2\)\(=\frac{\sqrt{a}\left(1-a\right)+\left(1-a\right)}{1+\sqrt{a}}\)\(.\left(\frac{1}{1-\sqrt{a}}\right)^2\)\(=\frac{\left(\sqrt{a}+1\right)\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)}{1+\sqrt{a}}\)\(.\left(\frac{1}{1-\sqrt{a}}\right)^2\)=  \(\frac{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)1^2}{\left(1-\sqrt{a}\right)^2}\)
= \(\frac{1+\sqrt{a}}{1-\sqrt{a}}\)