Tìm số nguyên x , biết :
a/ -19 + ( 13 - x ) = -2
b/ 11 + x - 24 = 21
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1/Tìm số nguyên x biết :
a/ 14 - ( 2 - x ) = 5
b/ -19 + ( 13 - x ) = -2
c/ 11 + x - 24 =21
Câu 11: Phân tích số 120 ra thừa số nguyên tố: A) 8.3.5 B) 24.3.5 C) 23.3.5 D) 15.23 Câu 12: Phân tích số 210 ra thừa số nguyên tố: A) 2.3.5.7 B) 2.3.4.5 C) 5.6.7 D) 23.3.5 Câu 13: Tìm số tự nhiên x biết x – 24 = 𝟑𝟐 A) x = 30 B) x = 21 C) x = 33 D) x = 15 2 / 2 Câu 14: Kết quả của phép tính 𝟔𝟎−𝟓.[𝟐𝟗−(𝟔−𝟏)𝟐] là: A) 40 B) 45 C) 220 D) −35 Câu 15: Viết tập hợp A bằng cách liệt kê phần tử: A = { 𝑥∈𝑍| −4
Bài 1: Tìm x nguyên, biết:
a) x + 5 = 20 - (12 -7)
b)15 - (3+ 2x) = 22
c) -11 - (19 - x) = 50
d)159 - (25 - x) = 43
e) (79 - x) - 43 = - (17 - 52)
f) (7 + x) - (21 - 13) = 32
g) - x + 20 = (-15) + 8 + 13
h) - (-x + 13 -142) + 18 = 55
Xin cảm ơn!
a) \(x+5=20-\left(12-7\right)\)
\(\Rightarrow x+5=20-5\)
\(\Rightarrow x+5=15\)
\(\Rightarrow x=15-5\)
\(\Rightarrow x=10\)
b) \(15-\left(3+2x\right)=2^2\)
\(\Rightarrow3+2x=15-4\)
\(\Rightarrow3+2x=11\)
\(\Rightarrow2x=11-3\)
\(\Rightarrow2x=8\)
\(\Rightarrow x=\dfrac{8}{2}\)
\(\Rightarrow x=4\)
c) \(-11-\left(19-x\right)=50\)
\(\Rightarrow19-x=-11-50\)
\(\Rightarrow19-x=-61\)
\(\Rightarrow x=61+19\)
\(\Rightarrow x=80\)
d) \(159-\left(25-x\right)=43\)
\(\Rightarrow25-x=159-43\)
\(\Rightarrow25-x=116\)
\(\Rightarrow x=25-116\)
\(\Rightarrow x=-91\)
e) \(\left(79-x\right)-43=-\left(17-52\right)\)
\(\Rightarrow\left(79-x\right)-43=52-17\)
\(\Rightarrow79-x-43=35\)
\(\Rightarrow36-x=35\)
\(\Rightarrow x=1\)
f) \(\left(7+x\right)-\left(21-13\right)=32\)
\(\Rightarrow7+x-8=32\)
\(\Rightarrow x-1=32\)
\(\Rightarrow x=32+1\)
\(\Rightarrow x=33\)
g) \(-x+20=-15+8+13\)
\(\Rightarrow-x+20=6\)
\(\Rightarrow x=20-6\)
\(\Rightarrow x=14\)
h) \(-\left(-x+13-142\right)+18=55\)
\(\Rightarrow x-13+142+18=55\)
\(\Rightarrow x+147=55\)
\(\Rightarrow x=55-147\)
\(\Rightarrow x=-92\)
Tìm x biết (2/11*13+2/13*15+2/15*17+2/17*19+2/19*21)*462 - x = 19
\(\left(\frac{2}{11\times13}+\frac{2}{13\times15}+\frac{2}{15\times17}+\frac{2}{17\times19}+\frac{2}{19\times21}\right)\times462-x=19\)
\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right)\times462-x=19\)
\(\left(\frac{1}{11}-\frac{1}{21}\right)\times462-x=19\)
\(\frac{10}{231}\times462-x=19\)
\(20-x=19\)
\(\Rightarrow x=20-19=1\)
tìm số nguyên x, biết
a,-(-x + 13 - 142 ) + 18 = 55
b, 25 - 3.(6 - x ) = 22
c, [( 2x - 11) : 3 + 1].5 = 20
d,3( x + 5 ) - x - 11 = 24
-( -x + 13 - 142 ) + 18 = 55
-( -x - 129) + 18 = 55
x + 129 + 18 = 55
x + 147 = 55
x = 55 - 147
x = -92
b, 25 - 3.(6 -x ) = 22
3(6-x) = 25 - 22
3(6-x) = 3
6 - x = 1
x =5
c, [ ( 2x - 11 ) :3 +1] .5 = 20
( 2x - 11) : 3 + 1 = 20 : 5
(2x - 11) : 3 + 1 = 4
( 2x - 11) : 3 = 4 - 1
(2x - 11 ) : 3 = 3
2x - 11 = 3 x 3
2x - 11 = 9
2x = 9 + 11
2x = 20
x = 10
d, 3(x+5) - x - 11 = 24
3(x+5) - x = 24 +11
3x + 15 - x = 35
2x = 35 - 15
2x = 20
x = 10
tìm x
(2/11*13+2/13*15 + ... 2/19*21)*462 - [0.04/(x+1.05)] /0.12=19
`(2/(11.13)+2/(13.15)+....+2/(19.21)).462-[0,04/(x+1,05):0,12=19`
`=>(1/11-1/13+1/13-1/15+....+1/19-1/21).462-(2/(50(x+1,05)).25/3=19`
`=>(1/11-1/21).462-1/(3(x+1,05))=19`
`=>10/231. 462-1/(3x+3,15)=19`
`=>20-1/(3x+3,15)=19
`=>1/(3x+3,15)=1`
`=>3x+3,15=1`
`=>3x=-2,15`
`=>x=-43/60`
Vậy `x=-43/60`
Giải:
\(\left(\dfrac{2}{11.13}+\dfrac{2}{13.15}+...+\dfrac{2}{19.21}\right).462-\left[\dfrac{0,04}{x+1,05}:0,12\right]=19\)
\(\left(\dfrac{1}{11}-\dfrac{1}{13}+\dfrac{1}{13}-\dfrac{1}{15}+...+\dfrac{1}{19}-\dfrac{1}{21}\right).462-\left[\dfrac{1}{\dfrac{25}{x+\dfrac{21}{20}}}:\dfrac{3}{25}\right]=19\)
\(\left(\dfrac{1}{11}-\dfrac{1}{21}\right).462-\left[\dfrac{1}{25.\left(x+\dfrac{21}{20}\right)}:\dfrac{3}{25}\right]=19\)
\(20-\left[\dfrac{25.1}{3.25.\left(x+\dfrac{21}{20}\right)}\right]=19\)
\(\dfrac{1}{3.\left(x+\dfrac{21}{20}\right)}=20-19\)
\(\dfrac{1}{3.x+\dfrac{63}{20}}=1\)
\(1:\left(3.x+\dfrac{63}{20}\right)=1\)
\(3.x+\dfrac{63}{20}=1:1\)
\(3.x+\dfrac{63}{20}=1\)
\(3.x=1-\dfrac{63}{20}\)
\(3.x=\dfrac{-43}{20}\)
\(x=\dfrac{-43}{20}:3\)
\(x=\dfrac{-43}{60}\)
tìm x biết:
a/ 3/2*x-70/10/11:(131313/151515+131313/353535+131313/999999)=-5
b/ 0,25*x*(8/5:1/1/2+1/50)=7/50*(2,91+0,09)*4
c/ (2/11*13+2/13*15+...+2/19*21) *462-(0,04:(x + 1,05)):0,12=19
bài 3 :tìm các số nguyên x , y biết :
a) x/3 = 7/y
b ) x/y = -13/11
c ) x/y-1 = 5/-19
a, x=7 y=3
b, x=-13 y=11
c, x=5 y=-18
h tôi đi
\(a,\frac{x}{4}=\frac{7}{x}\)
\(\Rightarrow x\cdot y=7\cdot4=\)
Tìm số nguyên x, biết:
a) (25 + x) - 25 = 0; b) ( -19) - ( x- 19) = 0;
c) 15 + ( x - 10) = 23; d) 19- ( - 13 + x) = 40