`d) ( 0,75 - 2x) : 13/49 = 7/26`
3/7(7/13-3/7) - 7/13( -3/7+26/49)
\(\frac{3}{7}\left(\frac{7}{13}-\frac{3}{7}\right)-\frac{7}{13}\left(-\frac{3}{7}+\frac{26}{49}\right)\)
\(=\frac{3}{7}\left(\frac{49}{91}-\frac{39}{91}\right)-\frac{7}{13}\left(-\frac{21}{49}+\frac{26}{49}\right)\)
\(=\frac{3}{7}.\frac{10}{91}-\frac{7}{13}.\frac{5}{49}\)
\(=\frac{30}{637}-\frac{5}{91}=\frac{30}{637}-\frac{35}{637}=\frac{-5}{637}\)
3/7(7/13-3/7) - 7/13( -3/7+26/49)
Tính hợp lý:
a, \(\dfrac{-3}{4}.5\dfrac{3}{13}-0,75.\dfrac{36}{13}\)
b, \(4\dfrac{5}{9}:\left(\dfrac{-5}{7}\right)+\dfrac{49}{9}:\left(\dfrac{-5}{7}\right)\)
c, \(\left(\dfrac{-3}{5}+\dfrac{4}{9}\right):\dfrac{7}{11}+\left(\dfrac{-2}{5}+\dfrac{5}{9}\right):\dfrac{7}{11}\)
d, \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}:\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
*Trả lời :
a) \(-\dfrac{3}{4}.5\dfrac{3}{13}-0,75.\dfrac{36}{13}\)
= \(-\dfrac{3}{4}.\dfrac{68}{13}-\dfrac{3}{4}.\dfrac{36}{13}\)
=\(\dfrac{3}{4}.\dfrac{-68}{13}-\dfrac{3}{4}.\dfrac{36}{13}\)
=\(\dfrac{3}{4}.\cdot\left(\dfrac{-68}{13}-\dfrac{36}{13}\right)\)
=\(\dfrac{3}{4}.\left(-8\right)\)
= \(-6\)
b)\(4\dfrac{5}{9}:\left(-\dfrac{5}{7}\right)+\dfrac{49}{9}:\left(-\dfrac{5}{7}\right)\)
=\(\dfrac{41}{9}-\left(-\dfrac{5}{7}\right)+\dfrac{49}{9}:\left(-\dfrac{5}{7}\right)\)
=\(\left(\dfrac{41}{9}+\dfrac{49}{9}\right):\left(-\dfrac{5}{7}\right)\)
=\(\dfrac{90}{9}:\left(-\dfrac{5}{7}\right)\)
=\(10:\left(-\dfrac{5}{7}\right)\)
=\(-14\)
c)\(\left(-\dfrac{3}{5}+\dfrac{4}{9}\right):\dfrac{7}{11}+\left(-\dfrac{2}{5}+\dfrac{5}{9}\right):\dfrac{7}{11}\)
=\(\left(-\dfrac{3}{5}\right)+\dfrac{4}{9}:\dfrac{7}{11}+\left(-\dfrac{2}{5}\right)+\dfrac{5}{9}:\dfrac{7}{11}\)(áp dụng tính chất phá ngoặc )
=\(\left\{\left[-\dfrac{3}{5}+\left(-\dfrac{2}{5}\right)\right]+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\right\}:\dfrac{7}{11}\)
=\(\left(-\dfrac{5}{5}+\dfrac{9}{9}\right):\dfrac{7}{11}\)
=\(\left(-1+1\right):\dfrac{7}{11}\)
\(=0:\dfrac{7}{11}\)
=0.
d)\(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}:\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
=\(\dfrac{6}{7}:\left[\dfrac{3}{26}+\left(-\dfrac{6}{26}\right)\right]+\dfrac{6}{7}:\left[\dfrac{1}{10}+\left(-\dfrac{16}{10}\right)\right]\)
=\(\dfrac{6}{7}:\left(-\dfrac{3}{26}\right)+\dfrac{6}{7}:\left(-\dfrac{3}{2}\right)\)
=\(\dfrac{6}{7}:\left[\left(-\dfrac{3}{26}\right)+\left(-\dfrac{39}{26}\right)\right]\)
=\(\dfrac{6}{7}:\left(-\dfrac{21}{13}\right)\)
=\(-\dfrac{26}{49}\)
Tìm giá trị lớn nhất hoặc nhỏ nhất của các đa thức sau:
A =\(\dfrac{37}{x^2-2x+3}\) B \(=\dfrac{-26}{x^2-5x+10}\) C \(=\dfrac{-2023}{x^2-x+6}\) D \(=\dfrac{0,75}{x^2+x+5}\) E \(=\dfrac{13}{2x^2-x+37}\) F \(=\dfrac{-61}{3x^2-x+19}\)
0,75 x 26 + 49 x 3/4 + 3/4 x24 + 0,75
3/7 x 1/2 + 0,5 x 4/7 + 0,125
1/3 x 4/5 + 2/3 + 1/3 + 6/5 x 16 + 84 x 1/8
Giúp mk giải chích xác
a) \(0,75\times26+49\times\frac{3}{4}+\frac{3}{4}\times24+\) \(0,75\)
\(=\) \(0,75\times\left(26+1\right)+\frac{3}{4}\times\left(49+24\right)\)
\(=\) \(\frac{3}{4}\times27+\frac{3}{4}\times73\)
\(=\) \(\frac{3}{4}\times\left(27+73\right)\)
\(=\)\(\frac{3}{4}\times100=75\)
b) câu b,c làm tương tự
1. tìm x
a. 71-(33+x)=26
b. (x+73)-26=76
c. 45-(x+9)=6
d. 89-(73-x)=20
e. (x+7)-25=13
f. 198-(x+4)=120
g. 140:(x-8)=7
h. 4(x+41)=400
i. 11(x-9)=77
j. 5(x-9)=350
k. 2x-49=5 .3 mũ 2
l.200-(2x+6)=4 mũ 3
a) 71 - (33 + x) = 26
⇔ 71 - 33 - x = 26
⇔ 38 - x = 26
⇔ x = 38 - 26
⇔ x = 12
b) (x + 73) - 26 = 76
⇔ x + 73 - 26 = 76
⇔ x + 47 = 76
⇔ x = 76 - 47
⇔ x = 29
c) 45 - (x + 9) = 6
⇔ 45 - x - 9 = 6
⇔ 36 - x = 6
⇔ x = 36 - 6
⇔ x = 30
d) 89 - (73 - x) = 20
⇔ 89 - 73 + x = 20
⇔ 16 + x = 20
⇔ x = 20 - 16
⇔ x = 4
e) (x + 7) - 25 = 13
⇔ x + 7 - 25 = 13
⇔ x - 18 = 13
⇔ x = 13 + 18
⇔ x = 31
f) 198 - (x + 4) = 120
⇔ 198 - x - 4 = 120
⇔ 194 - x = 120
⇔ x = 194 - 120
⇔ x = 74
g) 140 : (x - 8) = 7
⇔ x - 8 = 140 : 7
⇔ x - 8 = 20
⇔ x = 20 + 8
⇔ x = 28
h) 4(x + 41) = 400
⇔ x + 41 = 400 : 4
⇔ x + 41 = 100
⇔ x = 100 - 41
⇔ x = 59
i) 11(x - 9) = 77
⇔ x - 9 = 77 : 11
⇔ x - 9 = 7
⇔ x = 7 + 9
⇔ x = 16
j) 5(x - 9) = 350
⇔ x - 9 = 350 : 5
⇔ x - 9 = 70
⇔ x = 70 + 9
⇔ x = 79
k) 2x - 49 = 5.32
⇔ 2x - 49 = 45
⇔ 2x = 45 + 49
⇔ 2x = 94
⇔ x = 94 : 2
⇔ x = 47
l) 200 - (2x + 6) = 43
⇔ 200 - 2x - 6 = 64
⇔ 194 - 2x = 64
⇔ 2x = 194 - 64
⇔ 2x = 130
⇔ x = 130 : 2
⇔ x = 65
a) 71 - (33 + x) = 26
⇔ 33+x=71-26
⇔ 33 + x = 45
⇔ x = 45 - 33
⇔ x = 12
Vậy x=12
b) (x + 73) - 26 = 76
⇔ (x + 73) = 76+26
⇔ x + 73 = 102
⇔ x = 102-73
⇔ x = 29
Vậy x=29
c) 45 - (x + 9) = 6
⇔ x + 9 = 45 - 6
⇔ x+9 = 39
⇔ x = 39 - 9
⇔ x = 30
Vậy x=30
d) 89 - (73 - x) = 20
⇔ 73 - x = 89 - 20
⇔ 73 - x = 69
⇔ x = 73 - 69
⇔ x = 4
Vậy x=4
e) (x + 7) - 25 = 13
⇔ x + 7 = 13 + 25
⇔ x + 7 = 38
⇔ x = 38 - 7
⇔ x = 31
Vậy x=31
f) 198 - (x + 4) = 120
⇔ x + 4 = 198 -120
⇔ x + 4 = 78
⇔ x = 78 - 4
⇔ x = 74
Vậy x=74
kết quả của phép tính 24/13:12/26+49/15:7/30
\(\dfrac{24}{13}:\dfrac{12}{26}+\dfrac{49}{15}:\dfrac{7}{30}\)
\(=\dfrac{24}{13}\times\dfrac{26}{12}+\dfrac{49}{15}\times\dfrac{30}{7}\)
\(=4+14\)
\(=18\)
trên bản đồ tỉ lệ 1 : 2 000 000 , quãng đường từ Nha Trang Trang đến thành phố Hồ Chí Minh đo được 22 cm . Hỏi quãng đường đó trên thực tế dài bao nhiêu ki - lô - mét ?
tim tỉ số A/B biết
A=34/7*13+51/13*22+85/22*37+68/37*49
B=39/7*16+65/16*31+52/31*43+26/43*49
3. Kết quả phép tính là 24/13:12/26+49/15:7/30
Kết quả phép tính là 24/13:12/26+49/15:7/30
Kết quả bằng = 18
Nhớ like cho mình nhé Bb Hh!
Câu 2: Chọn câu sai?
A.\(\dfrac{1}{3}=\dfrac{45}{135}\)
B.\(\dfrac{-13}{20}=\dfrac{26}{-40}\)
C. \(\dfrac{-4}{15}=\dfrac{-16}{-60}\)
D. \(\dfrac{6}{7}=\dfrac{-42}{-49}\)