-25.2023-25.(-22)-(-25)
Rút gọn rồi tính
a) 22/25 + 25/125 + 36/96
b) 22/77 + 56/98 + 25/105
a)\(\dfrac{22}{25}+\dfrac{25}{125}+\dfrac{36}{96}\)
\(=\dfrac{22}{25}+\dfrac{1}{5}+\dfrac{3}{8}\)
\(=\dfrac{176}{200}+\dfrac{40}{200}+\dfrac{75}{200}\)
\(=\dfrac{291}{200}\)
b)\(\dfrac{22}{77}+\dfrac{56}{98}+\dfrac{25}{105}\)
\(=\dfrac{2}{7}+\dfrac{4}{7}+\dfrac{5}{21}\)
\(=\dfrac{6}{7}+\dfrac{5}{21}\)
\(=\dfrac{18}{21}+\dfrac{5}{21}=\dfrac{23}{21}\)
$x=\root(3)(22\sqrt(2+)25-\root(3)(22\sqrt(2))- 25)$
Đặt \(A=\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}\)
\(\Rightarrow A^3=50-3\sqrt[3]{\left(22\sqrt{2}+25\right)\left(22\sqrt{2}-25\right)}\left(\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}\right)\)
\(\Rightarrow A^3=50-3\sqrt[3]{\left(22\sqrt{2}+25\right)\left(22\sqrt{2}-25\right)}\cdot A\)
\(\Rightarrow A^3=50-3A\sqrt[3]{343}=50-21A\)
\(\Rightarrow A^3+21A-50=0\Leftrightarrow A^3-4A+25A-50=0\)
\(\Leftrightarrow\left(A-2\right)\left(A^2+2A+25\right)=0\)
\(\Leftrightarrow A=2\left(A^2+2A+25>0,\forall A\right)\)
\(\Rightarrow\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}=2\)
Tick nha bạn 😘
22/25.(5/11-8/9)-8/9.(27/4-22/25)
\(\frac{22}{25}.\left(\frac{5}{11}-\frac{8}{9}\right)-\frac{8}{9}\left(\frac{27}{4}-\frac{22}{25}\right)\)
\(\frac{22}{25}.\left(\frac{5}{11}-\frac{8}{9}\right)-\frac{8}{9}.\left(\frac{27}{4}-\frac{22}{25}\right)=\frac{22}{25}.\frac{5}{11}-\frac{22}{25}.\frac{8}{9}-\frac{8}{9}.\frac{27}{4}+\frac{8}{9}.\frac{22}{25}=\frac{2}{5}-\frac{6}{1}=\frac{-28}{5}\)
22/25. (5/11-8/9)-8/9. (27/4-22/25)
tính nhanh: (25-12 ) x ( 25- 22) x ... x ( 25-1002)
20+21+22+.....+29+30=
=(20+30)+(21+....)+(22+.....)+(23+.....)+(24+....)+25
=50........+25
tính nhanh tổng 20+21+22+...+29+30
20+21+22+23+24+25+26+27+28+29+30=
=(20+30)+(21+29)+(22+28)+(23+27)+(24+26)+25
=50+50+50+50+50+25
=50.5+25
=250+25
=275
tính nhanh
25 x 323 - 22 x 25 -25
\(25\times323-22\times25-25\\ =25\times\left(323-22-1\right)\\ =25\times300\\ =7500\)
\(=25.\left(323-22-1\right)\)
\(=25.300=7500\)
18/25 x y+25%-17%=22
Choose the mistake from the underline words.
22 *
25 điểm
A
B
C
D
23 *
25 điểm
A
B
C
D
22.A ( many => much)
23. C ( so=> but)
Rút gọn:
\(\frac{2^{35}.45^{25}.13^{22}.35^{16}}{9^{26}.65^{22}.28^{17}.25^9}\)
Ta có:
\(\frac{2^{35}.45^{25}.13^{22}.35^{16}}{9^{26}.65^{22}.28^{17}.25^9}=\frac{2^{35}.\left(9.5\right)^{25}.13^{22}.\left(5.7\right)^{16}}{9^{26}.\left(5.13\right)^{22}.\left(7.4\right)^{17}.\left(5.5\right)^9}\)
\(=\frac{2^{35}.9^{25}.5^{25}.13^{22}.5^{16}.7^{16}}{9^{26}.13^{22}.5^{22}.7^{17}.4^{17}.5^9.5^9}\)
\(=\frac{2^{35}.5^3}{9.4^{17}.5^2.7}\)
\(=\frac{2^{35}.5}{9.4^{17}.7}\)
\(=\frac{2^{35}.5}{9.2^{34}.7}\)
\(=\frac{2.5}{9.7}\)
\(=\frac{10}{63}\)
p/s: - Ko chắc ~
\(\frac{2^{35}.45^{25}.13^{22}.35^{16}}{9^{26}.65^{22}.28^{17}.25^9}=\frac{2^{35}.5^{25}.9^{25}.13^{22}.5^{16}.7^{16}}{9^{26}.5^{22}.13^{22}.4^{17}.7^{17}.5^9.5^9}=\frac{2^{35}.5^3.5^7}{9.\left(2^2\right)^{17}.7.5^9}=\frac{2^{35}.5^3}{9.2^{34}.7.5^2}=\frac{2.5}{9.7}=\frac{10}{63}\)