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2+3/4=11/4 ; 2-3/5=7/5
5/7:6=5/42 ; 5+2/7=37/7
Bài 2: a) x-1/6=1/2+1/3
x-1/6=5/6
x=5/6+1/6
x=1
b) x+1/8=1/2-1/3
x+1/8=1/6
x=1/6-1/8
x=1/24
c) x:1/2=2/3.3/4
x:1/2=1/2
x=1/2.1/2
x =1/4
Ta có: a x 2/3 + a x 7/3 = 9
a x (2/3+7/3) = 9
a x 3=9
a=9:3
a=3
a) \(63^7< 64^7=\left(2^6\right)^7=2^{42}< 2^{48}=\left(2^4\right)^{12}=16^{12}\Rightarrow63^7< 16^{12}\)
b) \(3^{151}>3^{150}=\left(3^2\right)^{75}=9^{75}>8^{75}=\left(2^3\right)^{75}=2^{225}\)
c) \(9^{20}=\left(3^2\right)^{20}=3^{40}>3^{39}=\left(3^3\right)^{13}=27^{13}\Rightarrow9^{20}>27^{13}\)
bài 2:
a)\(2^x=32\Leftrightarrow2^x=2^5\Leftrightarrow x=5\)
b)\(2x+3^4=7^2\Leftrightarrow2x+81=49\Leftrightarrow2x=-32\Leftrightarrow x=-16\)
c)\(12x-33=3^2\Leftrightarrow12x-33=9\Leftrightarrow12x=42\Leftrightarrow x=\frac{7}{2}\)
a, 7\(\dfrac{3}{5}\) : \(x\) = 5\(\dfrac{4}{15}\) - 1\(\dfrac{1}{6}\)
\(\dfrac{38}{5}\) : \(x\) = \(\dfrac{79}{15}\) - \(\dfrac{7}{6}\)
\(x\) = \(\dfrac{41}{10}\)
\(x\) = \(\dfrac{38}{5}\) : \(\dfrac{41}{10}\)
\(x\) = \(\dfrac{76}{41}\)
b, \(x\) \(\times\) 2\(\dfrac{2}{3}\) = 3\(\dfrac{4}{8}\) + 6\(\dfrac{5}{12}\)
\(x\) \(\times\) \(\dfrac{8}{3}\) = \(\dfrac{7}{2}\) + \(\dfrac{77}{12}\)
\(x\) \(\times\) \(\dfrac{8}{3}\) = \(\dfrac{119}{12}\)
\(x\) = \(\dfrac{119}{12}\)
\(x\) = \(\dfrac{119}{12}\): \(\dfrac{8}{3}\)
\(x\) = \(\dfrac{119}{32}\)
a) X*5,2 : 4,5 =10,4
X*5,2=10,4*4,5
X*5,2=46,8
X =46,8:5,2
X =9
b) 5/7*x+2/7*x=2/3
(5/7+2/7)*x=2/3
1*x =2/3
x =2/3:1
x =2/3
a) 123ab chia hết cho 2 và 5 nên b=0
123a0 chia hết cho 9 nên (1+2+3+a+0) chia hết cho 3
=>(6+a) chia hết cho 3
=>a=0;a=3;a=6;a=9
b)3ab chia hết cho 5 nên b=0 hoặc b=5
+với b=5:
3a5 chia 9 dư 4 nên (3+a+5) chia 9 dư 4
=>(8+a) chia 9 dư 4;
=>a=5
mà 355 chia 7 dư 5=>ko thỏa mãn
+với b=0:
3a0 chia 9 dư 4 nên (3+a+0) chia 9 dư 4;
=>(3+a) chia 9 dư 4;
=>a=1
Mà 310 chia 7 dư 2 => số cần tìm là 310
Mình chỉ làm 1 câu thôi nhé
a,
Ta có:
\(\frac{1}{7}+\frac{2}{7x}=\frac{3}{2}\)
\(\Rightarrow\frac{x+2}{7x}=\frac{3}{2}\)
=> 2x+4=21x
=> 4=19x
=> x=4/19
Chắc vậy á :)
\(\frac{1}{7}+\frac{2}{7}:x=\frac{3}{2}\)
\(\Rightarrow\frac{2}{7}:x=\frac{3}{2}-\frac{1}{7}\)
\(\Rightarrow\frac{2}{7}:x=\frac{21}{14}-\frac{2}{14}\)
\(\Rightarrow\frac{2}{7}:x=\frac{19}{14}\)
\(\Rightarrow x=\frac{2}{7}:\frac{19}{14}\)
\(\Rightarrow x=\frac{2}{7}\times\frac{14}{19}\)
\(\Rightarrow x=\frac{4}{19}\)
Vậy \(x=\frac{4}{19}\)
~ Ủng hộ nhé
sorry tui làm sai câu này!!!
2/3 +4/37 +5/111 +260 /1443
=962/1443+156/1443+65/1443+260/1443
= 962+156+65+260/1443=1
tìm x
1)1/2 - ( x+3/14) = 1/6
=> x+3/14=1/2-1/6
=> x= 1/3 - 3/14
=> x= 5/42
2)( x- 1/3 ) -5/2 = 1/7
=> x-1/3= 1/7+5/2
=> x= 37/14+1/3
=> x= 125/42
3)5/8 + ( x- 1/4 ) = 4/3
=>x-1/4=4/3-5/8
=>x= 17/24 +1/4
=> x= 23/24
4) 4/3 - ( 1/4 -x ) =1
=>1/4-x=4/3-1
=>x=1/4-1/3
=> x= -1/12
Chúc bạn Hk tốt!!!
2/3 +4/37 +5/111 +260 /1443\(=\frac{635}{629}\)
Tìm x
1. \(x=\frac{5}{42}\)
2. \(x=\frac{125}{42}\)
3. \(x=\frac{23}{24}\)
4. \(x=-\frac{1}{12}\)
Chúc bạn Hk tốt!!!