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a) \(4590:\left(x-24+14\right)=30\)
\(x-24+14=4590:30\)
\(x-24+14=153\)
\(x-24=153-14\)
\(x-24=139\)
\(x=139+24\)
\(x=163\)
b) \(61\times\left(126:x\right)=1281\)
\(126:x=1281:61\)
\(126:x=21\)
\(x=126:21\)
\(x=6\)
a) 4590 ÷ ( x− 24 + 14 ) = 30
4590 ( x- 10 ) = 30
x - 10 = 4590 : 30
x-10 = 153
x = 153+10
x = 163
a/ (x . 3) : 4 = 57
=> x . 3 = 228
=> x = 76
b/ (9 . x) : 7 = 126
=> 9 . x = 882
=> x = 98
a) (x x 3) : 4 = 57
(x x 3) = 57 x 4
(x x 3) = 228
x = 228 : 3
x = 76
b) (9 x x) : 7 = 126
(9 x x) = 126 x 7
(9 x x) = 882
x = 882 : 9
x = 98
4.x+1/2.3+1/3.4+1/4.5+1/5.6=1
4.x+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6=1
4x+1-1/6=1
4x=1-5/6
4x=1/6
x=1/6:4
x=1/24
Chúc Học Tốt!!!
\(a,\left(\frac{5}{7}+\frac{9}{7}\right)x\frac{21}{28}\)
\(C1:=\frac{14}{7}x\frac{21}{28}=\frac{3}{2}\)
\(C2:=\frac{5}{7}x\frac{21}{28}+\frac{9}{7}x\frac{21}{28}=\frac{15}{28}+\frac{27}{28}=\frac{3}{2}\)
\(b,\frac{4}{5}x\frac{13}{14}+\frac{13}{14}x\frac{1}{5}\)
\(C1:=\frac{26}{35}+\frac{13}{70}=\frac{13}{14}\)
\(C2:=\frac{13}{14}x\left(\frac{4}{5}+\frac{1}{5}\right)=\frac{13}{14}x1=\frac{13}{14}\)
học tốt ~~~
Bài 1 :
\(a)\) Ta có :
\(3x=4y=6z\)
\(\Leftrightarrow\)\(\frac{3x}{12}=\frac{4y}{12}=\frac{6z}{12}\)
\(\Leftrightarrow\)\(\frac{x}{4}=\frac{y}{3}=\frac{z}{2}\)
\(\Leftrightarrow\)\(\frac{2x}{8}=\frac{y}{3}=\frac{5z}{10}\)
Áp dụng tính chất dãy tỉ số bằng nhau ta có :
\(\frac{2x}{8}=\frac{y}{3}=\frac{5z}{10}=\frac{2x-5z}{8-10}=\frac{-36}{-2}=18\)
Do đó :
\(\frac{x}{4}=18\)\(\Rightarrow\)\(x=18.4=72\)
\(\frac{y}{3}=18\)\(\Rightarrow\)\(y=18.3=54\)
\(\frac{z}{2}=18\)\(\Rightarrow\)\(z=18.2=36\)
Vậy \(x=72\)\(;\)\(y=54\) và \(z=36\)
Chúc bạn học tốt ~
2) Ta có: \(\frac{a}{b+c}=\frac{b}{c+a}=\frac{c}{a+b}\)
Áp dụng tính chất dãy tỉ số bằng nhau ta có:
\(\frac{a}{b+c}=\frac{b}{c+a}=\frac{c}{a+b}=\frac{a+b+c}{b+c+c+a+a+b}=\frac{a+b+c}{2.\left(a+b+c\right)}=\frac{1}{2}\)
\(\Rightarrow\frac{a}{b+c}=\frac{1}{2}\Rightarrow2a=b+c\)
\(\frac{b}{c+a}=\frac{1}{2}\Rightarrow2b=c+a\)
\(\frac{c}{a+b}=\frac{1}{2}\Rightarrow2c=a+b\)
Ta có: \(\left(1+\frac{a}{b}\right)\left(1+\frac{b}{c}\right)\left(1+\frac{c}{a}\right)=\frac{b+a}{b}.\frac{c+b}{c}.\frac{a+c}{a}=\frac{2c.2a.2b}{b.c.a}=8\)
Vậy \(\left(1+\frac{a}{b}\right)\left(1+\frac{b}{c}\right)\left(1+\frac{c}{a}\right)=8\)
\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{100}\right).200x=4036\)
\(\Leftrightarrow\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.....\frac{99}{100}.200x=4036\)
\(\Leftrightarrow\frac{1.2.3...99}{2.3.4....100}.200x=4036\)
\(\Leftrightarrow\frac{1}{100}.200x=4036\)
\(\Leftrightarrow\frac{1}{100}.200x=4036\)
\(\Leftrightarrow2x=4036\)
\(\Leftrightarrow x=4036:2=2018\)
\(\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times...\times\left(1-\frac{1}{100}\right)\times200\times x=4036\)
=> \(\frac{1}{2}\times\frac{2}{3}\times...\times\frac{99}{100}\times200\times x=4036\)
=> \(\frac{1\times2\times...\times99}{2\times3\times...\times100}\times200\times x=4036\)
\(\Rightarrow\frac{1}{100}\times200\times x=4036\)
\(\Rightarrow2\times x=4036\)
=> x = 2018
a, 4590:(x-24+14)=30
x-24+14=4590 : 30
x-24+14=153
x-24=153-14
x-24=139
x=139+24
x=163
phần b mik ko bt