Tìm x
a) [ - 35 + (- x ) - 18 ] + ( 36+ 19 -8) = 40
bài 15 tìm x biết
a x4−37+25=31140x4−37+25=31140
b512+5x−18=12512+5x−18=12
c x+19−35=36x+19−35=36
d 34−x+6−11=5634−x+6−11=56
e x−19−35=36x−19−35=36
mik cần gấp! giúp mình với
Come on viết đề bài cho tử tế đi bạn (:
nhiều thế, ai lm nổi
1)tính
a)-17+(-19)+25=
b)-26+(-25)-18=
c)35-(-19)-19-8=
d)1963-(-180)-1990
2)Tìm x thuộc z biết
a)x-(-18)=25+(-17)
b)x-28=-27-30
c)35-(-x)=27-17-(-8)
d)40+(-x)=35-(-27)
nhanh nha các bạn để mai mình đi học
1)tính
a)\(-17+\left(-19\right)+25\)
\(=-17-19+25\)
\(=-\left(17+19\right)+25\)
\(=-36+25\)
\(=-\left(36-25\right)\)
\(=-11\)
b)\(-26+\left(-25\right)-18\)
\(=-26-25-18\)
\(=-\left(26+25\right)-18\)
\(=-51-18\)
\(=-\left(51+18\right)\)
\(=-69\)
c)\(35-\left(-19\right)-19-8\)
\(=35+19-19-8\)
\(=35+\left(19-19\right)-8\)
\(=35+0-8\)
\(=35-8\)
\(=27\)
d)\(1963-\left(-180\right)-1990\)
\(=1963+180-1990\)
\(=2143-1990\)
\(=153\)
2)Tìm x thuộc z biết
a)\(x-\left(-18\right)=25+\left(-17\right)\)
\(\Leftrightarrow x+18=25-17\)
\(\Leftrightarrow x+18=8\)
\(\Leftrightarrow x=8-18\)
\(\Leftrightarrow x=-10\)
Vậy x=-10
b)\(x-28=-27-30\)
\(\Leftrightarrow x-28=-\left(27+30\right)\)
\(\Leftrightarrow x-28=-57\)
\(\Leftrightarrow x=-57+28\)
\(\Leftrightarrow x=-\left(57-28\right)\)
\(\Leftrightarrow x=-29\)
Vậy x=-29
c)\(35-\left(-x\right)=27-18-\left(-8\right)\)
\(\Leftrightarrow35+x=27-18+8\)
\(\Leftrightarrow35+x=9+8\)
\(\Leftrightarrow35+x=17\)
\(\Leftrightarrow x=17-35\)
\(\Leftrightarrow x=-18\)
Vậy x=-18
d)\(40+\left(-x\right)=35-\left(-27\right)\)
\(\Leftrightarrow40-x=35+27\)
\(\Leftrightarrow40-x=62\)
\(\Leftrightarrow x=40-62\)
\(\Leftrightarrow x=-22\)
Vậy x=-22
BTVN
1. Tìm x thuộc Z, bt:
a, 15-x=20
b, (-27) +x=-19
c, x -(-39) = -2
d, (35-x)-19=-40
e) (-46)-(x-12)=59
g) (36+x)-(-46)=-20
Bài 2: Tìm x:
a) 156 – (x+ 61) = 82 b) (x-35) -120 = 0 c) 124 + (118 – x) = 217 d) 7x – 8 = 713 e) x- 36:18 = 12 f) (x- 36):18 = 12 g) (x-47) -115 = 0 |
|
|
Bài 3: Tính nhanh
a) 58.75 + 58.50 – 58.25 b) 27.39 + 27.63 – 2.27 c) 128.46 + 128.32 + 128.22 d) 66.25 + 5.66 + 66.14 + 33.66 e) 12.35 + 35.182 – 35.94 | f) 48.19 + 48.115 + 134.52 g) 27.121 – 87.27 + 73.34 h) 125.98 – 125.46 – 52.25 i) 136.23 + 136.17 – 40.36 j) 17.93 + 116.83 + 17.23 | k) 35.23 + 35.41 + 64.65 l) 29.87 – 29.23 + 64.71 m) 19.27 + 47.81 + 19.20
|
Bài 4: Tính giá trị của biểu thức sau:
a) 2763 + 152 b) (-7) + (-14) c) (-35) + (-9) d) (-5) + (-248) e) (-23) + 105 f) 78 + (-123) g) 23 + (-13) h) (-23) + 13 i) 26 + (-6) | j) 80 + (-220) k) (-23) + (-13) l) (-26) + (-6) | m) 12 – 34 n) -23 – 47 o) 31 – (-23) p) -9 – (-5) q) 6 – (8 – 17) r) 19 + (23 – 33) s) (-12 – 44) + (-3) t) 4 – (-15) u) -29 – 23 | v) 99 – [109 + (-9)] w) (-75) + 50 x) (-75) + (-50) y) (-23) + 13 + ( - 17) + 57 z) 14 + 6 + (-9) + (-14)
|
a: =>x+61=74
hay x=13
b: =>x-35=120
hay x=155
d: =>7x=721
hay x=103
x-35/21 + x-36/20 > x-37/19 + x-38/18
Ta có : \(\frac{x-35}{21}+\frac{x-36}{20}>\frac{x-37}{19}+\frac{x-38}{18}\)(1)
\(\Leftrightarrow\left(\frac{x-35}{21}-1\right)+\left(\frac{x-36}{20}-1\right)\)\(-\left(\frac{x-37}{19}-1\right)-\left(\frac{x-38}{18}-1\right)\)\(>0\)
\(\Leftrightarrow\frac{x-56}{21}+\frac{x-56}{20}-\frac{x-56}{19}-\frac{x-56}{18}\)\(>0\)
\(\Leftrightarrow\left(x-56\right)\left(\frac{1}{21}+\frac{1}{20}-\frac{1}{19}-\frac{1}{18}\right)\)\(>0\)
Vì \(\frac{1}{21}+\frac{1}{20}-\frac{1}{19}-\frac{1}{18}< 0\)
\(\Rightarrow x-56< 0\)\(\Leftrightarrow x< 56\)
Vậy tập nghiệm của BPT(1) là \(S=\left\{x\in R|x< 56\right\}\)
35 + 36 + 37 + 38 + 39 + 40 - 20 - 19 - 18 - 17 - 16 - 15
35 + 36 + 37 + 38 + 39 + 40 - 20 - 19 - 18 - 17 - 16 - 15=?
=120
hok tốt !
= (35 - 15) + (36 - 16) + (37 - 17) + (38 - 18) + (39 - 19) + (40 - 20)
=20 + 20 + 20 + 20 + 20 +20
=120
ok ?
Câu 15: Tìm x thuộc bội của 9 và x < 63
A. x ∈ {0; 9; 18; 27; 36; 45; 54} B. x ∈ {0; 9; 18; 28; 35}
C. x ∈ {9; 18; 27; 36; 45; 54; 63} D. x ∈ {9; 18; 27; 36; 45; 55; 63}
2. Tìm x biết : a) 13.(25-4x)=13 b) (2x-4).15=0 c) (x-35)-115=0 d) x-36:18=12 e) (x-36):18=12
a: =>25-4x=1
=>4x=24
hay x=6
b: =>2x-4=0
hay x=2
c: =>x-35=115
hay x=150
d: =>x-2=12
hay x=14
e: =>x-36=216
hay x=252
a) 9/22 x 33/18 =
b) 12/35 : 36/25 =
c) 19/17 : 76/51 =
a) 9/22 x 33/18 =3/4
b) 12/35 : 36/25 = 5/21
c) 19/17 : 76/51 =3/4
a) \(\frac{9}{22}\times\frac{33}{18}\)
\(=\frac{9}{22}\times\frac{11}{6}\)
\(=\frac{9\times11}{22\times6}=\frac{3}{4}\)
b) \(\frac{12}{35}:\frac{36}{25}=\frac{12}{35}\times\frac{25}{36}\)
\(=\frac{5}{21}\)
c) \(\frac{19}{17}:\frac{76}{51}=\frac{19}{17}\times\frac{51}{76}\)
\(=\frac{3}{4}\)
\(a,\frac{9}{22}x\frac{33}{18}\)
\(=\frac{3.3.11.3}{11.2.3.3.2}\)
\(=\frac{3}{2.2}\)
\(=\frac{3}{4}\)
\(b,\frac{12}{35}:\frac{36}{25}\)
\(=\frac{12}{35}.\frac{25}{36}\)
\(=\frac{12.25}{35.36}\)
\(=\frac{12.5.5}{5.7.12.3}\)
\(=\frac{5}{7.3}\)
\(=\frac{5}{21}\)
\(c,\frac{19}{17}:\frac{76}{51}\)
\(=\frac{19}{17}.\frac{51}{76}\)
\(=\frac{19.51}{17.76}\)
\(=\frac{19.17.3}{17.19.4}\)
\(=\frac{3}{4}\)