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a) 10*(x-1)=15-5
10*(x-1)=10
(x-1)=10:10
(x-1)=1
x=1+1
x=2
b) x+1+x+2+x+3=18
3x+6=18
3x=18-6
3x=12
x=12:3
x=4
c) 17+2*(x+2)=25
2*(x+2)=25-17
2*(x+2)=8
x+2=8:2
x+2=4
x=4-2
x=2
d) x:17=82-17+26
x:17=91
x=91*17
x=1547
e) 147*x=441
x=441:147
x=3
g)(x:81)=330:10:11
(x:81)=3
x=3*81
x=243
i)x+1+x+2+x+3+x+4+x+5=40
5x+15=40
5x=40-15
5x=25
x=5
Ủng hộ nha
bạn làm sao ấy đề mink viet khac ma ban vite mot neo
\(1) 420+65.4=(x+175):5+30\)
\(\implies 420+260=(x+175):5+30\)
\(\implies 680=(x+175):5+30\)
\(\implies 650=(x+175):5\)
\(\implies 650.5-175=x\)
\(\implies 3075=x\)
\(2)x-4867=(175.2050.70):25+23\)
\(\implies x-4867=1004500+23\)
\(\implies x-4867=1004523\)
\(\implies x=1009390\)
\(3) 134-[(96-7x):4-2]=126\)
\(\implies (96-7x):4-2=8\)
\(\implies(96-7x):4=10\)
\(\implies 96-7x=40\)
\(\implies 7x=56\)
\(\implies x=8\)
\(4) 4-\{100-[(100-5x):8-5]:10\}:25=0\)
\(\implies 4-\{100-[(100-5x):8-5]:10\}=0\)
\(\implies 100-[(100-5x):8-5]:10=4\)
\(\implies 100-[(100-5x):8-5]=40\)
\(\implies (100-5x):8-5=60\)
\(\implies (100-5x):8=65\)
\(\implies 100-5x=520\)
\(\implies 5x=-420\)
\(\implies x=-84\)
~ Hok tốt a~
882:(2x-15)=18
2x-15=882:18
2x-15=49
2x=49+15
2x=64
x=32
k mk nha
mk nhanh nhất
117 - 2 x ( x - 25 ) = 89
2 x ( x - 25 ) = 89 + 117
2 x ( x - 25 ) = 206
x - 25 = 206 : 2
x - 25 = 103
x = 105 + 25
x = 130
Học tốt nhé!!! Arigatou
117 - 2 x ( X - 25 ) = 89
2 x ( X - 25 ) = 117- 89
2 x ( X - 25 ) = 28
X - 25 = 28 : 2
X - 25 = 14
X = 14 + 25
X = 29
Vậy X = 29
Đề bài kiểu gì vậy?
Nếu như là \(117-2\times\left(x-25\right)=89\) thì:
\(117-2\times\left(x-25\right)=89\)
\(2\times\left(x-25\right)=117-89\)
\(2\times\left(x-25\right)=28\)
\(x-25=\frac{28}{2}\)
\(x-25=14\)
\(x=14+25\)
\(x=39\)
Còn nếu là \(117-2x\left(x-25\right)=89\) thì :
\(117-2x\left(x-25\right)=89\)
\(2x\left(x-25\right)=117-89\)
\(2x\left(x-25\right)=28\)
\(x\left(x-25\right)=14\)
\(x^2-25x=14\)
\(x^2-25x-14=0\)
\(\Delta=25^2+4\cdot1\cdot14=681>0\)
\(x_1=\frac{25+\sqrt{681}}{2};x_2=\frac{25-\sqrt{681}}{2}\)
Lần sau phải viết đề bài rõ hơn.
117-2x(x-25)=89
2x(x-25)=117-89
2x(x-25)=28
x-25=28:2
x-25=14
x=14+25
x=39
1)\(A=\frac{1}{3}+\frac{1}{6}+...+\frac{1}{55}=2\left(\frac{1}{6}+\frac{1}{12}+...+\frac{1}{110}\right)=2\left(\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{10.11}\right)=2\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{10}-\frac{1}{11}\right)=2.\left(\frac{1}{2}-\frac{1}{11}\right)=\frac{9}{11}\)
2) Tử số = 11 x 13 x 15 + 3 x 3 x 3 x 11 x 13 x 15 + 5 x 5 x 5 x 11 x 13 x 15 + 9 x 9 x 9 x 11 x 13 x 15
= (1 + 3 x 3 x 3 + 5 x 5 x 5 + 9 x 9 x9) x 11 x 13 x 15 = (1+27+125+ 729) x 11 x 13 x 15
Mẫu số = 11 x 13 x 17 + 3 x 3 x 3 x 13 x 15 x 19 + 5 x 5 x 5 x 13 x 15 x 17 + 9 x 9 x 9 x 13 x 15 x 17
lớn hơn 11 x 13 x 15 + 3 x 3 x 3 x 13 x 15 x 17 + 5 x 5 x 5 x 13 x 15 x 17 + 9 x 9 x 9 x 13 x 15 x 17
= (1 + 3 x 3 x 3 + 5 x 5 x 5 + 9 x 9 x9) 13 x 15 x 17 = (1+27+125+729) x 13 x 15 x 17
=> \(A<\frac{\left(1+27+125+729\right)\times11\times13\times15}{\left(1+27+125+729\right)\times13\times15\times17}=\frac{11}{17}=\frac{1111}{1717}=B\)
Vậy A < B
\(\left(117+30\right)\cdot x=882:2\)
\(147\cdot x=441\)
\(x=441:147\)
\(x=3.\)
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