rút gọn các biểu thức
(-6).11 / (-11).(-8)
21.(-5) / 25.(-7)
32.9.11 / 12.24.22
Bài 4: Rút gọn các phân số:
a)\(\dfrac{\left(-2\right).7}{7.5}\)=
b)\(\dfrac{\left(-21\right).\left(-5\right)}{15.\left(-7\right)}\)=
c)\(\dfrac{72.75}{125.108}\)=
d)\(\dfrac{32.9.11}{12.24.22}\)=
rút gọn phân số
\(\dfrac{32.9.11}{12.24.22}\)
rút gọn nhanh nhất nhé
\(\dfrac{32.9.11}{12.24.22}\) = \(\dfrac{8.4.3.3.11}{3.4.8.3.11.2}\) = \(\dfrac{1}{2}\)
\(\dfrac{32.9.11}{12.24.22}=\dfrac{8.4.3.3.11}{3.4.8.3.11.2}=\dfrac{1}{2}\)
thu gọn các biểu thức sau
a)C=3^14+3^15+3^16+3^17+...+3^n
b)D=3^11+3^14+3^17+3^20+...+3^2021
c) E= -5^2-5^4-5^6-5^8-...-5^1000
d)F=-5^21-5^23-5^25-5^27-...-5^2019
e)M=7^2-7^4+7^6-7^8+...-7^1000
d)N=-12+11^2+11^3-11^4-11^5+...+11^498+11^499
b: \(27D=3^{14}+3^{17}+...+3^{2024}\)
\(\Leftrightarrow26D=3^{2024}-3^{11}\)
hay \(D=\dfrac{3^{2024}-3^{11}}{26}\)
c: \(25E=-5^4-5^6-...-5^{1002}\)
\(\Leftrightarrow24E=-5^{1002}+5^2\)
hay \(E=\dfrac{-5^{1002}+5^2}{24}\)
rút gọn biểu thức sau
3 .16 /12.9
11.5 -11.7 /11
6 /11 - 6/9 +6 /5 /21/11- 21/9+21/5
Rút gọn biểu thức: a) 2x + (- 61) - (21 - 61); b) (- 3 - x + 5) + 3 c) 11 - (13 - x) + (13 - 11); d) 25 - (15 - x + 303) +303
Rút gọn biểu thức:
a) 2x + (- 61) - (21 - 61);
b) (- 3 - x + 5) + 3;
c) 11 - (13 - x) + (13 - 11);
d) 25 - (15 - x + 303) +303.
a) 2x + (-61) - (21 - 61) = 2x - 21 + (61 - 61) = 2x - 21.
b) (- 3 - x + 5) + 3 = (- 3 + 3) + 5 - x = 5 - x.
c) 11- (13 - x) + (13 - 11) = (11- 11) + (13- 13) + x = x
d) 25 - ( 15 - x + 303) + 303 = 25 - 15 + (303 - 303) + x = x + 10
Câu 1: Rút gọn các biểu thức sau:
C = \(\dfrac{8^2.9^5}{3^9.4^3}\)
D = \(\dfrac{81^6.9^5}{27^7.3^{11}}\)
F = \(\dfrac{8^{15}.25^7}{125^5.2^{47}}\)
G = \(\dfrac{10^2.5^3}{8.25^2}\)
\(C=\dfrac{2^6\cdot3^{10}}{3^9\cdot2^6}=3\\ D=\dfrac{3^{24}\cdot3^{10}}{3^{21}\cdot3^{11}}=\dfrac{3^{34}}{3^{32}}=3^2=9\\ F=\dfrac{2^{45}\cdot5^{14}}{5^{15}\cdot2^{47}}=\dfrac{1}{2^2\cdot5}=\dfrac{1}{20}\\ G=\dfrac{2^2\cdot5^2\cdot5^3}{2^3\cdot5^4}=\dfrac{1\cdot5}{2}=\dfrac{5}{2}\)
C=3
D=9
F=1/20
G=5/2
Em ko giải chi tiết vì nó lâu
Mong thông cảm!
C= \(\dfrac{8^2.9^5}{3^9.4^3}\)
= \(\dfrac{\left(2^3\right)^2.\left(3^2\right)^5}{3^9.\left(2^2\right)^3}\)
= \(\dfrac{2^6.3^{10}}{3^9.2^6}\)
= \(\dfrac{3^1}{1}\)
= \(\dfrac{3}{1}\)
Rút gọn biểu thức
1)\(\sqrt{6+\sqrt{32}}\) - \(\sqrt{11-\sqrt{72}}\)
2) \(\sqrt{21-4\sqrt{5}}\) + \(\sqrt{21+4\sqrt{5}}\)
1) \(\sqrt{6+4\sqrt{2}}-\sqrt{11-6\sqrt{2}}\)
\(=\sqrt{2^2+2\cdot2\cdot\sqrt{2}+\left(\sqrt{2}\right)^2}-\sqrt{3^2-2\cdot3\cdot\sqrt{2}+\left(\sqrt{2}\right)^2}\)
\(=\sqrt{\left(2+\sqrt{2}\right)^2}-\sqrt{\left(3-\sqrt{2}\right)^2}\)
\(=\left|2+\sqrt{2}\right|-\left|3-\sqrt{2}\right|\)
\(=2+\sqrt{2}-3+\sqrt{2}\)
\(=2\sqrt{2}-1\)
2) \(\sqrt{21-4\sqrt{5}}+\sqrt{21+4\sqrt{5}}\)
\(=\sqrt{20-4\sqrt{5}+1}+\sqrt{20+4\sqrt{5}+1}\)
\(=\sqrt{\left(2\sqrt{5}\right)^2-2\sqrt{5}\cdot2\cdot1+1^2}+\sqrt{\left(2\sqrt{5}\right)^2+2\sqrt{5}\cdot2\cdot1-1^2}\)
\(=\sqrt{\left(2\sqrt{5}-1\right)^2}+\sqrt{\left(2\sqrt{5}+1\right)^2}\)
\(=\left|2\sqrt{5}-1\right|+\left|2\sqrt{5}+1\right|\)
\(=2\sqrt{5}-1+2\sqrt{5}+1\)
\(=4\sqrt{5}\)
Thực hiện phép tính (rút gọn biểu thức)
a)\(\left(\sqrt{3}-2\right)\sqrt{7+4\sqrt{3}}\)
b) \(\sqrt{6+\sqrt{32}}\) - \(\sqrt{11-\sqrt{72}}\)
c) \(\sqrt{21-4\sqrt{5}}\) + \(\sqrt{21+4\sqrt{5}}\)
a: \(=\left(\sqrt{3}-2\right)\cdot\sqrt{\left(2+\sqrt{3}\right)^2}\)
\(=\left(\sqrt{3}-2\right)\left(\sqrt{3}+2\right)\)
=3-4=-1
b: \(=\sqrt{6+4\sqrt{2}}-\sqrt{11-2\sqrt{18}}\)
\(=\sqrt{\left(2+\sqrt{2}\right)^2}-\sqrt{\left(3-\sqrt{2}\right)^2}\)
\(=2+\sqrt{2}-3+\sqrt{2}=2\sqrt{2}-1\)
c: \(=\sqrt{\left(2\sqrt{5}-1\right)^2}+\sqrt{\left(2\sqrt{5}+1\right)^2}\)
\(=2\sqrt{5}-1+2\sqrt{5}+1\)
\(=4\sqrt{5}\)