1. Tìm y :
Y x 7:5 + 4x 8 = 134
2. Tính nhanh
\(\dfrac{1}{4}\): 0,25 - \(\dfrac{1}{8}\) : 0,125 + \(\dfrac{1}{2}\) : 0,5 -\(\dfrac{1}{10}\)
Tính giá trị biểu thức:
\(\dfrac{1}{2}\) : 0,5 - \(\dfrac{1}{4}\) : 0,25 + \(\dfrac{1}{8}\) : 0,125 - \(\dfrac{1}{10}\) : 0,1
\(\frac{1}{2}:0,5-\frac{1}{4}:0,25+\frac{1}{8}:0,125-\frac{1}{10}:0,1\)
\(=\frac{1}{2}\times2-\frac{1}{4}\times4+\frac{1}{8}\times8-\frac{1}{10}\times10\)
\(=1-1+1-1\)
\(=0\)
Tính bằng cách thuận tiện nhất
a, \(\dfrac{1}{10}+\dfrac{2}{10}+\dfrac{3}{10}+\dfrac{4}{10}+\dfrac{5}{10}+\dfrac{6}{10}+\dfrac{7}{10}+\dfrac{8}{10}+\dfrac{9}{10}\)
b, 13,25 : 0,5 + 13,25 : 0,25 + 13,25 : 0,125 + 13,25 x 6
Giúp mình với mình đang gấp
\(\dfrac{1}{10}+\dfrac{2}{10}+\dfrac{3}{10}+\dfrac{4}{10}+\dfrac{5}{10}+\dfrac{6}{10}+\dfrac{7}{10}+\dfrac{8}{10}+\dfrac{9}{10}\)
\(=\left(\dfrac{1}{10}+\dfrac{9}{10}\right)+\left(\dfrac{2}{10}+\dfrac{8}{10}\right)+\left(\dfrac{3}{10}+\dfrac{7}{10}\right)+\left(\dfrac{4}{10}+\dfrac{6}{10}\right)+\dfrac{5}{10}\)
\(=1+1+1+1+\dfrac{5}{10}\)
\(=4+\dfrac{5}{10}\)
\(=\dfrac{45}{10}\)
\(13,25:0,5+13,25:0,25+13,25:0,125+13,25\times6\)
\(=13,25:\dfrac{1}{2}+13,25:\dfrac{1}{4}+13,25:\dfrac{1}{8}+13,25\times6\)
\(=13,25\times2+13,25\times4+13,25\times8+13,25\times6\)
\(=13,25\times\left(2+4+8+6\right)\)
\(=13,25\times20\)
\(=265\)
bài 1 : Tìm y
\(\dfrac{7}{8}xy-\dfrac{6}{4}=\dfrac{3}{2}\) \(\dfrac{2}{5}:y+\dfrac{1}{5}:y=\dfrac{10}{3}\)
bài 2 : Tính nhanh
\(\dfrac{2}{5}x\dfrac{4}{7}+\dfrac{2}{5}x\dfrac{3}{7}\) \(\dfrac{2}{9}:\dfrac{2}{3}:\dfrac{3}{9}\)
Bài 1:
+) \(\dfrac{7}{8}\times y=\dfrac{3}{2}+\dfrac{6}{4}=3\)
\(y=3:\dfrac{7}{8}=\dfrac{24}{7}\)
+) \(\dfrac{1}{y}\times\left(\dfrac{2}{5}+\dfrac{1}{5}\right)=\dfrac{10}{3}\)
\(\dfrac{1}{y}=\dfrac{10}{3}:\dfrac{3}{5}=\dfrac{50}{9}\)
\(y=\dfrac{9}{50}\)
Bài 2:
+) \(=\dfrac{2}{5}\times\left(\dfrac{4}{7}+\dfrac{3}{7}\right)\)
\(=\dfrac{2}{5}\times\dfrac{7}{7}=\dfrac{2}{5}\)
+) \(\dfrac{2}{9}:\dfrac{2}{3}:\dfrac{3}{9}\)
\(\dfrac{2}{9}\times\dfrac{3}{2}\times\dfrac{9}{3}=1\)
Lời giải:
$\frac{1}{4}:0,25-\frac{1}{8}:0,125:0,5-\frac{1}{10}$
$=\frac{1}{4}\times 4-\frac{1}{8}\times 8\times 2-0,1$
$=1-2-0,1=-1-0,1=-1,1$
1: trong các trường hợp sau, trường hợp nào các số cùng biểu thị một số hữu tỉ:
A) 0,5; \(\dfrac{5}{10}\); \(\dfrac{1}{2}\) B) o,4; 2; \(\dfrac{1}{2}\) C) 0,5; 0,25, 0,35 D) \(\dfrac{-5}{7}\) ; \(\dfrac{-5}{8}\); \(\dfrac{-5}{9}\)
Tìm y
\(\dfrac{2}{5}\) X y : \(\dfrac{7}{4}=\dfrac{7}{8}\)
2\(\dfrac{2}{5}\) : y x 1\(\dfrac{1}{4}\) = 2\(\dfrac{3}{5}\)
\(\dfrac{12}{5}-1\dfrac{2}{5}x\) y = 1\(\dfrac{1}{4}\)
\(\dfrac{2}{5}\) x y : \(\dfrac{7}{4}\) = \(\dfrac{7}{8}\)
\(\dfrac{2}{5}\) x y = \(\dfrac{7}{8}\) x \(\dfrac{7}{4}\)
\(\dfrac{2}{5}\) x y = \(\dfrac{49}{32}\)
y = \(\dfrac{49}{32}\) : \(\dfrac{2}{5}\)
y = \(\dfrac{245}{64}\)
2\(\dfrac{2}{5}\): y x 1\(\dfrac{1}{4}\) = 2\(\dfrac{3}{5}\)
\(\dfrac{12}{5}\): y x \(\dfrac{5}{4}\) = \(\dfrac{13}{5}\)
\(\dfrac{12}{5}\): y = \(\dfrac{13}{5}\): \(\dfrac{5}{4}\)
\(\dfrac{12}{5}\): y = \(\dfrac{52}{25}\)
y = \(\dfrac{12}{5}\): \(\dfrac{52}{25}\)
y = \(\dfrac{15}{13}\)
\(\dfrac{12}{5}\) - 1\(\dfrac{2}{5}\) \(\times\) y = 1\(\dfrac{1}{4}\)
\(\dfrac{12}{5}\) - \(\dfrac{7}{5}\) \(\times\) y = \(\dfrac{5}{4}\)
\(\dfrac{7}{5}\) \(\times\) y = \(\dfrac{12}{5}\) - \(\dfrac{5}{4}\)
\(\dfrac{7}{5}\) \(\times\) y = \(\dfrac{23}{20}\)
y = \(\dfrac{23}{20}\) : \(\dfrac{7}{5}\)
y = \(\dfrac{23}{28}\)
\(\dfrac{0,125-\dfrac{1}{5}+\dfrac{1}{7}}{0,375-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)
`=(0,125-1/5+1/7)/(3(0,125-1/5+1/7))+(2(1/4+1/6-0,1))/(3(1/4+1/6-0,1))`
`=1/3+2/3=3/3=1`
1, giải phương trình
a, 2( x - 0,5 ) + 3 = 0,25(4x - 1 )
b , 2.\(\left(x-\dfrac{1}{4}\right)-4=-6\left(-\dfrac{1}{3}x+0,5\right)+2\)
2, giải các phương trình
a, \(\dfrac{3x-2}{2}=\dfrac{1-2x}{3}\)
b, \(\dfrac{x-1}{3}+2=3-\dfrac{2x+5}{4}\)
c, \(\dfrac{x-1}{5}+x=\dfrac{x+1}{7}\)
d, 2(x - 2,5 ) = 0,25 +\(\dfrac{4x-3}{8}\)
các bạn ơi ! giúp mik với ! mai kiểm tra rồi
2.a)\(\dfrac{3\text{x}-2}{2}\)=\(\dfrac{1-2\text{x}}{3}\)
<=>\(\dfrac{9\text{x}-6}{6}\)=\(\dfrac{2-4\text{x}}{6}\)
<=>9x-6=2-4x
<=>9x+4x=2+6
<=>13x=8
<=>x=\(\dfrac{8}{13}\)
1.a)2(x-0,5)+3=0,25(4x-1)
<=>2x-1+3=x-1phần4
<=>2x-x=-1/4+1-3
<=>x=-3/4
a. 2( x - 0,5 ) + 3 = 0,25(4x - 1 )
(=) 2x - 1 + 3 = x - 0,25
(=) 2x - x = 1 - 3 - 0,25
(=) x = -2,25
b. 2. (x−14) −4 = −6 (−13x+0,5) +2
(=) 2x - 0.5 - 4 = 2x - 3 + 2
(=) 2x - 2x = 0,5 + 4 -3 +2 ( vô lí )
Vậy phương trình này vô nghiệm
Tính nhanh .
a, \(P=\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{7}{11}}\)
b, \(Q=\dfrac{0,125-\dfrac{1}{5}+\dfrac{1}{7}}{0,375-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)
a) Hình như nhầm đề thì phải :v
\(P=\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{6}{11}}\)
\(=\dfrac{\dfrac{5}{12}+\dfrac{5}{11}}{\dfrac{5}{12}+\dfrac{5}{11}}=1\)
b) \(Q=\dfrac{0,125-\dfrac{1}{5}+\dfrac{1}{7}}{0,375-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)
\(Q=\dfrac{0,125-\dfrac{1}{5}+\dfrac{1}{7}}{3\left(0,125-\dfrac{1}{5}+\dfrac{1}{7}\right)}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)
\(Q=\dfrac{1}{3}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)
\(Q=\dfrac{1}{3}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{5}}{\dfrac{3}{2}\left(\dfrac{1}{2}-\dfrac{1}{5}+\dfrac{1}{3}\right)}=\dfrac{1}{3}+\dfrac{1}{\dfrac{3}{2}}\)
\(Q=\dfrac{1}{3}+\dfrac{2}{3}=1\)
a,\(P=\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{7}{11}}=\dfrac{\left(\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}\right).132}{\left(\dfrac{5}{12}+1-\dfrac{7}{11}\right).132}=\dfrac{88-33+60}{55+132-84}=\dfrac{115}{103}\)
b, Ta có : 0,125 = \(\dfrac{1}{8}\) ; 0,375 = \(\dfrac{3}{8}\) ; 0,2 = \(\dfrac{1}{5}\) ; 0,5 = \(\dfrac{3}{6}\)
\(Q=\dfrac{\dfrac{1}{8}-\dfrac{1}{5}+\dfrac{1}{7}}{\dfrac{3}{8}-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{5}}{\dfrac{3}{4}+\dfrac{3}{6}-\dfrac{3}{10}}\)
\(Q=\dfrac{\dfrac{1}{8}-\dfrac{1}{5}+\dfrac{1}{7}}{3\cdot\left(\dfrac{1}{8}-\dfrac{1}{5}+\dfrac{1}{7}\right)}+\dfrac{2\cdot\left(\dfrac{1}{4}+\dfrac{1}{6}-\dfrac{1}{10}\right)}{3\cdot\left(\dfrac{1}{4}+\dfrac{1}{6}-\dfrac{1}{10}\right)}\)
\(Q=\dfrac{1}{3}+\dfrac{2}{3}=1\)