Tìm x biết x+x*2 +x * 3+8= 120
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a) x - 120: 30 = 40
x -40 =40
x =40+40
x =80
b) (x + 120) : 20 = 8
(x+ 120) = 8x20
x+120 =160
x = 160-120
x = 40
c) (x + 5). 3 = 300
x+5=300:3
x+5=100
x=100-5
x=95
d) x.2 + 21 : 3= 27
x.2 +7=27
x.2 = 27-7
x.2= 20
x=20:2
x=10
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a) 13 x ( x +1 ) =143
x+1= 143 : 13
x+1= 11
x= 11-1
x= 10
b) ( x - 2 ) : 7 = 12
x-2= 12 x 7
x-2=84
x=84+2
x=86
c) 120 : ( x - 3 )= 8
x-3=120:8
x-3=15
x=15+3
x=18
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`@` `\text {Ans}`
`\downarrow`
`a,`
`(x-1954) \times 5=50`
`x-1954 = 50 \div 5`
`x-1954 = 10`
`x=10 + 1954`
`x= 1964`
`B.`
`48 - 40 \times x=8`
`40 \times x=48-8`
`40 \times x = 40`
` x=40 \div 40`
`x=1`
`C.`
`2+70 \div x = 3`
`70 \div x = 3-2`
`70 \div x = 1`
`x=70 \div 1`
`x=70`
`D. [3 \times (x+2) \div 7] \times 4=120`
`3 \times (x+2) \div 7 = 120 \div 4`
`3 \times (x+2) \div 7 =30`
`3 \times (x+2) = 30 \times 7`
`3 \times (x+2)=210`
`x+2=210 \div 3`
`x+2=70`
`x=70-2`
`x=68`
`E.`
`7,2 \div [ (0,6 \times x+8) \div 20 + 59] = 0,12?` Thiếu ngoặc bạn nhé._.
\(a,\left(x-1954\right)\times5=50\\ x-1954=50:5\\ x-1954=10\\ x=1954+10\\ x=1964\\b.48-40\times x=8\\40\times x=48-8\\40\times x=40\\ x=40:40\\ x=1 \\ c.2+70:X=3\\ 70:x=3-2\\ 70:x=1\\ x=70:1\\ x=70\\ d,\left[3\times\left(x+2\right):7\right]\times4=120\\ 3\times\left(x+2\right):7-120:4\\ 3\times\left(x+2\right):7=30\\ \left(x+2\right):7=30:3\\ \left(x+2\right):7=10\\ x+2=10\times7\\ x+2=70\\ x=70-2\\ x=68\)
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\(a) \frac{4}{5}.x=\frac{8}{35}\)
\(\implies x= \frac{8}{35}:\frac{4}{5}\)
\(\implies x=\frac{8}{35}.\frac{5}{4}\)
\(\implies x=\frac{2}{7}\). Vậy \(x=\frac{2}{7}\)
\(b) \frac{3}{5}x-\frac{1}{2}=\frac{1}{7}\)
\(\implies \frac{3}{5}x=\frac{1}{7}+\frac{1}{2}\)
\(\implies \frac{3}{5}x=\frac{9}{14}\)
\(\implies x=\frac{9}{14}:\frac{3}{5}\)
\(\implies x=\frac{9}{14}.\frac{5}{3} \)
\(\implies x=\frac{15}{14}\). Vậy \(x=\frac{15}{14}\)
\(c) x-25\% x=0,5\)
\(\implies 75\% x=0,5\)
\(\implies \frac{3}{4}x=\frac{1}{2}\)
\(\implies x=\frac{1}{2}:\frac{3}{4}\)
\(\implies x=\frac{1}{2}.\frac{4}{3}\)
\(\implies x=\frac{2}{3}\). Vậy \(x=\frac{2}{3}\)
\(d) (\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}).120+x:\frac{1}{3}=-4\)
Có: \(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\)
\(=\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\)
\(=\frac{1}{24}-\frac{1}{30}\)
\(=\frac{1}{120}\)
Thay vào ta có: \(\frac{1}{120}.120+x:\frac{1}{3}=-4\)
\(\implies 1+x:\frac{1}{3}=-4\)
\(\implies x:\frac{1}{3}=-5\)
\(\implies x=-5.\frac{1}{3}\)
\(\implies x=\frac{-5}{3}\). Vậy \(x=\frac{-5}{3}\)
~ Hok tốt a~
\(\frac{4}{5}.x=\frac{8}{35}\) \(\frac{3}{5}x-\frac{1}{2}=\frac{1}{7}\)
\(x=\frac{8}{35}:\frac{4}{5}\) \(\frac{3}{5}x=\frac{1}{7}+\frac{1}{2}\)
\(x=\frac{8}{35}.\frac{5}{4}\) \(\frac{3}{5}x=\frac{9}{14}\)
\(x=\frac{2}{7}\) \(x=\frac{9}{14}:\frac{3}{5}\)
Vậy \(x=\frac{2}{7}\) \(x=\frac{9}{14}.\frac{5}{3}\)
\(x-25\%x=0.5\) \(x=\frac{15}{14}\)
\(x-\frac{1}{4}x=\frac{1}{2}\) Vậy \(x=\frac{15}{14}\)
\(x\left(1-\frac{1}{4}\right)=\frac{1}{2}\) \(\left(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\right).120+x:\frac{1}{3}=-4\)
\(x=\frac{1}{2}:\frac{3}{4}\) \(\left(\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\) \(x=\frac{2}{3}\) \(\left(\frac{1}{24}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)
Vậy \(x=\frac{2}{3}\) \(\frac{1}{120}.120+x:\frac{1}{3}=-4\)
\(1+x:\frac{1}{3}=-4\)
\(x:\frac{1}{3}=\left(-4\right)-1\)
\(x:\frac{1}{3}=-5\)
\(x=\left(-5\right).\frac{1}{3}\)
\(x=-\frac{5}{3}\)
Vậy \(x=-\frac{5}{3}\)
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ta se tinh nhu sau :
x : ( 8 + 3 - 10 ) * ( 32 + 18 - 10 ) = 120
x :1 * 40 = 120
x = 120 : 40 * 1
x = 30
mih hoc lop bon , neu sai thi gop y cho mih nha !! :))
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a. 20 + 8.(x + 3) = 52 . 4
8.(x + 3) = 100 - 20
x + 3 = 80 : 8
x = 10 - 3
x = 7
b. 120 + |x| = 150
|x| = 150 - 120
|x| = 30
x = + 30
a) 20 + 8(x + 3) = 52 . 4
20 + 8(x + 3) = 100
8(X + 3) = 100 - 20
8(x + 3) = 80
x + 3 = 80 : 8
x + 3 = 10
x = 10 - 3
x = 7
b) 120 + |x| = 150
|x| = 150 - 120
|x| = 30
=> \(\orbr{\begin{cases}x=30\\x=-30\end{cases}}\)
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Đề bài hơi lằng nhằng nên có 2 kiểu nhé bạn :
Nếu đề bài là 2x + 2x +1 +2x+2+2x + 3 =120
2x ( 1+2+3)=120
2x 6 = 120
2x= 120 : 6
2 mũ x =20
x thuộc rỗng :v
Đề kiểu 2 :
Nếu đề bài là 2x + 2x+1 +2x+2 2x+3 =120
Thì là : 2x.1 + 2x . 21+2x . 22 2x . 23 =120
2x ( 1+2+4+8) =120
2 mũ x . 15 =120
2 mũ x = 8
x= 3
mình bạn nhé :)
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(-2)+4+(-6)+8+.....+x=120
2+2+.....+x=120
mả đay tịnh 2+2+.....cộng lại là một số chẵn và tong cung la mot so chan
khi và chỉ khi x=2
BẠN NÈ NHỚ TÍCH ĐÚNG CHO MÌNH ĐẤY NHÉ