a) 210:[16+3.(6+3.2^2)]-3

=210:[16+3.(6+3.4)]-3

=210:[16+3.(6+12)]-3

=210:[16+3.18]-3

=210:[16+54]-3

=210:70-3

=3-3

=0

\(500-\left\{5.\left[409.\left(2^3.3-21\right)^2\right]\right\}-3\)

500-{5.[409.(8.3-21)^2]}-3

500-{5.[409.(24-21)^2]}-3

500-{5.[409.3^2]}-3

500-{5.[409.9]}-3

500-{5.3681}-3

500-18405-3

...............

tự làm nốt nha

\(10+2\cdot x=4^5:4^3\)

\(\Rightarrow10+2\cdot x=4^{5-3}\)

\(\Rightarrow10+2\cdot x=4^2\)

\(\Rightarrow10+2\cdot x=16\)

\(\Rightarrow2\cdot x=16-10\)

\(\Rightarrow2\cdot x=6\)

\(\Rightarrow x=\dfrac{6}{2}=3\)

__________________

\(2\cdot x-6^2:18=3\cdot2^2\)

\(\Rightarrow2\cdot x-36:18=12\)

\(\Rightarrow2\cdot x-2=12\)

\(\Rightarrow2\cdot x=12+2\)

\(\Rightarrow2\cdot x=14\)

\(\Rightarrow x=\dfrac{14}{2}=7\)

_________________

\(70-5\cdot\left(x-3\right)=3\cdot2\)

\(\Rightarrow70-5\cdot\left(x-3\right)=6\)

\(\Rightarrow70-5x+15=6\)

\(\Rightarrow-5x+15=6-70\)

\(\Rightarrow-5x+15=64\)

\(\Rightarrow-5x=64-15\)

\(\Rightarrow-5x=49\)

\(\Rightarrow x=-\dfrac{49}{5}\)

2: \(\dfrac{\sqrt{12}-\sqrt{5}}{\sqrt{2}-1}-\dfrac{1}{\sqrt{5}-2}\)

\(=\left(2\sqrt{3}-\sqrt{5}\right)\left(\sqrt{2}+1\right)-\sqrt{5}-2\)

\(=2\sqrt{6}+2\sqrt{3}-\sqrt{10}-\sqrt{5}-\sqrt{5}-2\)

\(=2\sqrt{6}+2\sqrt{3}-\sqrt{10}-2\sqrt{5}-2\)

3: \(=2\cdot3\sqrt{3}-6\cdot\dfrac{1}{\sqrt{3}}+2-\sqrt{3}-3\sqrt{3}\)

\(=6\sqrt{3}-2\sqrt{3}+2-4\sqrt{3}=2\)

1) \(\dfrac{3+\sqrt{3}}{\sqrt{5}}-\dfrac{2}{\sqrt{3}-1}\)

\(=\dfrac{\sqrt{5}\cdot\left(3+\sqrt{3}\right)}{\sqrt{5}\cdot\sqrt{5}}-\dfrac{2\left(\sqrt{3}+1\right)}{\left(\sqrt{3}-1\right)\left(\sqrt{3}+1\right)}\)

\(=\dfrac{3\sqrt{5}+\sqrt{15}}{5}-\dfrac{2\left(\sqrt{3}-1\right)}{3-1}\)

\(=\dfrac{3\sqrt{5}+\sqrt{15}}{5}-\left(\sqrt{3}-1\right)\)

\(=\dfrac{3\sqrt{5}+\sqrt{15}-5\sqrt{3}+5}{5}\)

2) \(\dfrac{\sqrt{12}-\sqrt{5}}{\sqrt{2}-1}-\dfrac{1}{\sqrt{5}-2}\)

\(=\dfrac{\left(2\sqrt{3}-\sqrt{5}\right)\left(\sqrt{2}+1\right)}{\left(\sqrt{2}-1\right)\left(\sqrt{2}+1\right)}-\dfrac{\sqrt{5}+2}{\left(\sqrt{5}-2\right)\left(\sqrt{5}+2\right)}\)

\(=\dfrac{2\sqrt{6}+2\sqrt{3}-\sqrt{10}-\sqrt{5}}{2-1}-\dfrac{\sqrt{5}+2}{5-4}\)

\(=2\sqrt{6}+2\sqrt{3}-\sqrt{10}-\sqrt{5}-\left(\sqrt{5}+2\right)\)

\(=2\sqrt{6}+2\sqrt{3}-\sqrt{10}-2\sqrt{5}-2\)

3) \(2\sqrt{27}-6\sqrt{\dfrac{1}{3}}+\dfrac{1}{2}+\dfrac{\sqrt{3}-9}{\sqrt{3}}\)

\(=2\cdot3\sqrt{3}-\dfrac{6}{\sqrt{3}}+\dfrac{1}{2}+\dfrac{\sqrt{3}\left(1-3\sqrt{3}\right)}{\sqrt{3}}\)

\(=6\sqrt{3}-\dfrac{\sqrt{3}\cdot2\sqrt{3}}{\sqrt{3}}+\dfrac{1}{2}+1-3\sqrt{3}\)

\(=6\sqrt{3}-2\sqrt{3}+\dfrac{1}{2}+1-3\sqrt{3}\)

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

\(=\dfrac{3}{2}+\sqrt{3}\)

x-3=7^5/7^3+2^3.2^2

x-3=7^2+2^5

x-3=49+32

x-3=81

x=81+3

x=84

Mở máy. Bấm tổ hợp phím:

a) 2 ( 3 x 5 \(x^2\) - 2 ( 5 + 7 ) ) +3 \(x^{[]}\) 3 =

Kết quả:129

b) 3 ( 120 + ( 55 - ( 11 - 3 x 2 ) \(x^2\) ) ) +2 \(x^{[]}\) 3 =

Kết quả: 458

hi các bạn

m trả lời ko thì biết

đề bài sai à

\(\frac{2^7.9^2}{3^3.2^5}\)\(=\frac{2^7.\left(3^2\right)^2}{3^3.2^5}=\frac{2^7.3^4}{3^3.2^5}=\frac{2^2.3}{1}=2^2.3=4.3=12\)

(-2).3³.5³.7.8/3.2⁴.5³.14

=(-378000)/84000

=-9/2