x + 1/2 = 3/4 : 3/2
2,4 x Y = 6/5 x 0,4
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1) 2,75 - 5/6 × 2/5 = 2,75 - (5/6) × (2/5) = 2,75 - 1/3 = 2,75 - 0,33 = 2,42
2) 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 3/4) - 3/5 = 1,25 - (5/6 - 9/12) - 3/5 = 1,25 - (10/12 - 9/12) - 3/5 = 1,25 - 1/12 - 3/5 = 1,25 - 0,08 - 0,6 = 1,25 - 0,68 = 0,57
3) 4/9 × 0,75 + 8/5 + 3,125 = (4/9) × 0,75 + 8/5 + 3,125 = 0,44 + 8/5 + 3,125 = 0,44 + 1,6 + 3,125 = 0,44 + 4,725 = 5,165
4) 1,125 - 4/7 - 0,12 = 1,125 - (4/7) - 0,12 = 1,125 - 0,57 - 0,12 = 0,435 - 0,12 = 0,315
5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5
a)
\(\begin{array}{l}5{x^4} - 2{x^3}y + 20x{y^3} + 6{x^3}y - 3{x^2}{y^2} + x{y^3} - {y^4}\\ = 5{x^4} + \left( { - 2{x^3}y + 6{x^3}y} \right) - 3{x^2}{y^2} + \left( {20x{y^3} + x{y^3}} \right) - {y^4}\\ = 5{x^4} + 4{x^3}y - 3{x^2}{y^2} + 21x{y^3} - {y^4}\end{array}\)
Bậc của đa thức là: 4
b)
\(\begin{array}{l}0,6{x^3} + {x^2}z - 2,7x{y^2} + 0,4{x^3} + 1,7x{y^2}\\ = \left( {0,6{x^3} + 0,4{x^3}} \right) + {x^2}z + \left( { - 2,7x{y^2} + 1,7x{y^2}} \right)\\ = {x^3} + {x^2}z - x{y^2}\end{array}\)
Bậc của đa thức là: 3
b. \(\dfrac{45}{100}:3-\dfrac{24,5}{100}:5\)
=\(0,45:3-0,245:5\)
= 0,15 - 0,049
= 0,101
c. 0,56 - \(\dfrac{12}{100}\)+ \(\dfrac{3}{4}-1\)
= 0,56 - 0,12 + 0,75 - 1
= 0,19
d. ( 0,4 x 7 - \(\dfrac{140}{100}\):0,5) x \(\left(\dfrac{2}{100}+\dfrac{4}{100}+\dfrac{6}{100}+...+1\right)\)
= (2,8 - 2,8 ) x (0,02 + 0,04 +0,06 +...+1)
=0
\(a.32,5-3\cdot0,87=32,5-2,61=29,89\)
\(8,5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8,5\cdot\left(\dfrac{3}{2}+\dfrac{4}{4}\right):5\\ =8,5\cdot\left(\dfrac{6}{4}+\dfrac{4}{4}\right):5\\ =8,5\cdot\dfrac{10}{4}:5\\ =\dfrac{85}{4}:5\\ =\dfrac{17}{4}\)
\(b.30,96-6,45+14,4:3=30,96-6,45+4,8\\ =29,31\)
\(\dfrac{2}{5}\cdot\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\cdot\left(\dfrac{8}{10}-\dfrac{5}{10}\right)\\ =\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{3}{25}\)
bài 2
\(a.2,5\cdot12,5\cdot8\cdot0,4=\left(2,5\cdot0,4\right)\left(12,5\cdot8\right)\\ =1\cdot100=100\)
b,\(\dfrac{12}{15}\cdot\dfrac{5}{6}\cdot\dfrac{3}{20}\cdot\dfrac{32}{5}=\dfrac{12\cdot5\cdot3\cdot32}{15\cdot6\cdot20\cdot5}\\ =\dfrac{3\cdot4\cdot5\cdot3\cdot4\cdot8}{3\cdot5\cdot2\cdot3\cdot5\cdot4\cdot5}=\dfrac{16}{25}\)
Bài 1:
a) \(32.5-3\cdot0.87=32.5-2.61=29.89\)
\(8.5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8.5\cdot\dfrac{5}{2}:5=\dfrac{17}{2}\cdot\dfrac{5}{2}:5=\dfrac{85}{4}\cdot\dfrac{1}{5}=\dfrac{17}{4}\)
a: \(\Leftrightarrow\left(\dfrac{13}{4}:x\right)\cdot\left(-\dfrac{5}{4}\right)=\dfrac{-10}{6}-\dfrac{5}{6}=\dfrac{-15}{6}=\dfrac{-5}{2}\)
\(\Leftrightarrow\dfrac{13}{4}:x=\dfrac{5}{2}\cdot\dfrac{5}{4}=\dfrac{25}{8}\)
hay \(x=\dfrac{13}{4}:\dfrac{25}{8}=\dfrac{13}{4}\cdot\dfrac{8}{25}=\dfrac{26}{25}\)
b: \(\Leftrightarrow\dfrac{3}{4}:x=\dfrac{11}{36}-\dfrac{1}{4}=\dfrac{2}{36}=\dfrac{1}{18}\)
=>\(x=\dfrac{3}{4}:\dfrac{1}{18}=\dfrac{54}{4}=\dfrac{27}{2}\)
c: \(\Leftrightarrow\left(-\dfrac{6}{5}+x\right):\left(-3.6\right)=-\dfrac{7}{4}+\dfrac{1}{4}\cdot8=\dfrac{1}{4}\)
=>x-6/5=-9/10
=>x=3/10
`x+1/2=3/4 : 3/2`
`=>x+1/2 = 3/4 . 2/3`
`=>x+1/2 = 1/2`
`=>x=1/2-1/2`
`=>x=0`
Vậy `x=0`
__
`2,4xx y = 6/5 xx 0,4`
`=> 24/10 xx y = 6/5 xx 4/10`
`=> 12/5 xx y = 6/5 xx 2/5`
`=> 12/5 xx y = 12/25`
`=> y = 12/25 : 12/5`
`=> y = 12/25 . 5/12`
`=> y = 5/25`
`=> y = 1/5`
Vậy `y=1/5`
`#QiN`