2+6=
12+6=
25-23
12-6
Tính hợp lí:
a) \(A=\left(\frac{3}{4}-\frac{4}{7}-\frac{5}{6}\right):\left(-\frac{3}{10}+\frac{4}{14}-\frac{-5}{12}\right)\left(\frac{1}{12}-\frac{7}{6}\right)\)
b) 123.(-234+4356-2312)+234.(123-2312)-2312.(-234-123)
a: \(A=\dfrac{63-48-70}{84}:\dfrac{-3\cdot84+4\cdot60+5\cdot70}{840}\cdot\dfrac{1-14}{12}\)
\(=\dfrac{-55}{84}\cdot\dfrac{840}{338}\cdot\dfrac{-13}{12}=\dfrac{55}{1}\cdot\dfrac{10}{338}\cdot\dfrac{13}{12}=\dfrac{275}{156}\)
b: \(=-234\cdot123+123\cdot4356-123\cdot2312+234\cdot123-234\cdot2312+2312\cdot234+2312\cdot123\)
\(=123\cdot4356-123\cdot2312+123\cdot2312=123\cdot4356=535788\)
Tìm x ∈ ℕ , biết:
a ) 5 6 + 1 6 ≤ x ≤ 13 4 + 14 8 b ) − 5 6 + 8 3 + 29 − 6 ≤ x ≤ − 1 2 + 2 + 5 2 c ) 79 15 + 7 5 + − 8 3 ≤ x ≤ 10 3 + 15 4 + 23 12
a) 1 ≤ x ≤ 5 => x ∈ {1;2;3;4;5}
b) -3 ≤ x ≤ 4 =>x ∈ {0;1;2;3;4}
c) 4 ≤ x ≤ 9 => x ∈ {4;5;6;7;8;9}
Tìm x thuộc N, biết:
a ) 5 6 + 1 6 ≤ x ≤ 13 4 + 14 8 b ) − 5 6 + 8 3 + 29 − 6 ≤ x ≤ − 1 2 + 2 + 5 2 c ) 79 15 + 7 5 + − 8 3 ≤ x ≤ 10 3 + 15 4 + 23 12
Tìm x thuộc Z, biết:
a) 5 6 + 1 6 ≤ x ≤ 13 4 + 14 8
b) − 5 6 + 8 3 + 29 − 6 ≤ x ≤ − 1 2 + 2 + 5 2
c) 79 15 + 7 5 + − 8 3 ≤ x ≤ 10 3 + 15 4 + 23 12
a) 5 6 + 1 6 ≤ x ≤ 13 4 + 14 8 ⇔ 1 ≤ x ≤ 5 ⇔ x ∈ 1 ; 2 ; 3 ; 4 ; 5
b) − 5 6 + 8 3 + 29 − 6 ≤ x ≤ − 1 2 + 2 + 5 2 ⇔ − 3 ≤ x ≤ 4 ⇔ x ∈ − 3 ; − 2 ; − 1 ; 0 ; 1 ; 2 ; 3 ; 4
c) 79 15 + 7 5 + − 8 3 ≤ x ≤ 10 3 + 15 4 + 23 12 ⇔ 4 ≤ x ≤ 9 ⇔ x ∈ 4 ; 5 ; 6 ; 7 ; 8 ; 9
12) √15-6√6 + √35-12√6
13) √46-6√5 - √29-12√5
14) (2-√3) √7+4√3
15) (4+√5)(√10-√6) √4-√15
16) √25-16 -6√1/3 - 2/1+√3
17) (1+√2+√3) (1+√2-√3)
12) \(\sqrt{15-6\sqrt{6}}+\sqrt{35-12\sqrt{6}}\)
\(=3-\sqrt{6}+3\sqrt{3}-2\sqrt{2}\)
13) \(\sqrt{46-6\sqrt{5}}-\sqrt{29-12\sqrt{5}}\)
\(=3\sqrt{5}-1-2\sqrt{5}+3\)
\(=\sqrt{5}+2\)
Bài 2: Thực hiện phép tính:
a) 125 + (-4).6 – (-3).(-25)
b) (-26).7 + 2.[(-18) + 15 – 20]
c) 24 – (-12).2 + (-3).(-6) \
d) (-18) – 6.[25 – 17.(-9) + 12]
mn giuos mình vs
A=56.611.162+62.126.152/2.612.104-812.9603
B=2528+2524+...+254+1/2530+2528+...+252+1
Trả lời giúp mình nha.
Tính giá trị biểu thức bằng cách hợp lí nhất:
a)6/10 + 6/11 + 7/13 + 2/5 + 16/11 + 19/13 =?
b)13/25 : 6/11 +12/25 : 6/11
a) -2/9 - 5/12 b) 2,25 - (-6/25) c) 5/12 - (-7/6)
Giúp mình với
a) \(-\dfrac{2}{9}-\dfrac{5}{12}\)
\(=-\dfrac{8}{36}-\dfrac{15}{36}\)
\(=-\dfrac{23}{36}\)
b) \(2,25-\left(-\dfrac{6}{25}\right)\)
\(=2,25+\dfrac{6}{25}\)
\(=2,49\)
c) \(\dfrac{5}{12}-\left(-\dfrac{7}{6}\right)\)
\(=\dfrac{5}{12}+\dfrac{14}{12}\)
\(=\dfrac{19}{12}\)
a) \(\dfrac{-2}{9}-\dfrac{5}{12}=\dfrac{-8}{36}-\dfrac{15}{36}=\dfrac{-23}{36}\)
b) \(2,25-\left(-\dfrac{6}{25}\right)=2,25+\dfrac{6}{25}=\dfrac{225}{100}+\dfrac{6}{25}=\dfrac{225}{100}+\dfrac{24}{100}=\dfrac{249}{100}\)
c) \(\dfrac{5}{12}-\left(-\dfrac{7}{6}\right)=\dfrac{5}{12}+\dfrac{7}{6}=\dfrac{5}{12}+\dfrac{14}{12}=\dfrac{19}{12}\)
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