7x - x = 521: 519 + 3.22 - 7
7x - x = 521: 519 + 3.22 - 7
7x - x = 30
7.x - 1.x = 30
x . (7-1) = 30
x . 6 = 30
x = 30 : 6
x = 5
DỄ ƠI LÀ DỄ
7x - x = 521 : 519 + 3.22 - 7 0
\(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(6x=5^2+3.2-1\)
\(6x=25+12-1\)
\(6x=36\)
\(x=6\)
K bt đk:))
Ta có :
7x - x = 521 : 519 . 3 . 22 - 70
=> 6x = 521: 519 + 3 . 22 - 70
=> 6x = 52 + 3. 4 - 1
=> 6x = 25 + 3 . 2 - 1
=> 6x = 25 + 6 - 1
=> 6x = 30
=> x = 30 : 6
=> x = 5
7x−x=521:519+3.22−70
6x=52+3.2−16x=52+3.2−1
6x=25+12−16x=25+12−1
6x=366x=36
x=6
a) 5x + x = 39 – 311:39 b) 2x : 25 = 16
| c) 7x – x = 521 : 519 + 3.22 - 70 d) 7x – 2x = 617: 615 + 44 : 11 |
a) \(5x+x=39-3^{11}:3^9\)
\(\Leftrightarrow6x=39-3^2\)
\(\Leftrightarrow6x=30\)
\(\Leftrightarrow x=5\)
b) \(2^x:2^5=16\)
\(\Leftrightarrow2^x:2^5=2^4\)
\(\Leftrightarrow2^x=2^4.2^5\)
\(\Leftrightarrow2^x=2^9\)
\(\Leftrightarrow x=9\)
c) \(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(\Leftrightarrow6x=5^2+3.4-1\)
\(\Leftrightarrow6x=36\)
\(\Leftrightarrow x=6\)
d) \(7x-2x=6^{17}:6^{15}+44:11\)
\(\Leftrightarrow5x=6^2+4\)
\(\Leftrightarrow5x=40\)
\(\Leftrightarrow x=8\)
a)⇔6x=39-32
⇔6x=30
⇔ x=5
b)2x:25=16
⇔2x=24.25
⇔ 2x=29
⇔ x=9
c)⇔6x=52+3.22-1
⇔ 6x= 36
⇔ x=6
d)⇔5x=62+4
⇔ 5x=40
⇔ x=8
a) 5x + 3x = 36 : 33.4 + 12
4x + 2x = 68 – 219 : 216
a) 5x + x = 39 – 311:39
b) 7x – x = 521 : 519 + 3.22 - 70
c) 7x – 2x = 617: 615 + 44 : 11
a: \(\Leftrightarrow6x=30\)
hay x=5
b: \(\Leftrightarrow6x=25+12-1=36\)
hay x=6
a) 5x + 3x = 36 : 33.4 + 12
4x + 2x = 68 – 219 : 216
a) 5x + x = 39 – 311:39
b) 7x – x = 521 : 519 + 3.22 - 70
c) 7x – 2x = 617: 615 + 44 : 11
a: \(\Leftrightarrow8x=108+12=120\)
hay x=15
b: \(\Leftrightarrow6x=60\)
hay x=10
a) 5x + 3x = 120
x . (5+3)= 120
x . 8 = 120
x = 120 : 8
x = 15
c) 7x - 2x = 40
x .(7-2)= 40
x . 5 = 40
x = 40 : 5
x = 8
Bài 27. Tìm x biết
a. 89 – (73 – x) = 20 b. (x + 7) – 25 = 13 c. 98 – (x + 4) = 20
d. 140 : (x – 8) = 7 e. 4(x + 41) = 400 f. x – [ 42 + (–28)] = –8
g. x + 5 = 20 – (12 – 7) h. (x – 11) = 2.2³ + 20 : 5 i. 4(x – 3) = 7² – 1³.
j. 2x+1.22014 = 22015. k. 2x – 49 = 5.3² ℓ. 3²(x + 14) – 5² = 5.2²
m. 6x + x = 511 : 59 + 31. n. 7x – x = 521 : 519 + 3.2² – 70.
o. 7x – 2x = 617 : 615 + 44 : 11. p. 3x = 9 q. 4x = 64
r. 9x–1 = 9 s. x4 = 16 t. 2x : 25 = 1
u. |x – 2| = 0 v. |x – 5| = 7 – (–3) w. |x – 5| = |–7|
x. |x| – 5 = 3 y. 15 – 2|x| = 13
a) 89-(73-x) = 20
=> 73+x =89-20
=> 73+x=69
=> x=69-73
=> x=-4
b) (x+7)-25=13
=> x+7=13+25
=> x+7=38
=> x=38-7
=> x=31
c) 98-(x+4)=20
=> x+4=98-20
=> x+4=78
=> x=78-4
=> x=73
d) 140:(x-8)=7
=> x-8=140:7
=> x-8=20
=> x=20+8
=> x=28
e) 4(x+41)=400
=> x+41=400:4
=> x+41=100
=> x=100-41
=> x=59
f) x-[42+(-28)]=-8
=> x-14=-8
=> x=-8+14
=> x=6
g) x+5=20-(12-7)
=> x+5=20-5
=> x+5=15
=> x=15-5
=> x=10
h) \(x-11=2.2^3+20:5\)
=> x-11=2.8+4
=> x-11=16+4
=> x-11=20
=> x=20+11
=> x=31
i) \(4\left(x-3\right)=7^2-1^3\)
=> 4(x-3)=49-1
=> 4(x-3)=48
=> x-3=48:4
=> x-3=12
=> x=12+3
=> x=15
Thực hiện phép tính (Tính nhanh nếu có thể)
a) 20 : 2 2 − 5 9 : 5 8
b) ( 5 19 : 5 17 − 4 ) : 7 0
c) 295 − ( 31 − 2 2 .5 ) 2
a) 20 : 2 2 − 5 9 : 5 8 = 5 − 5 = 0
b) ( 5 19 : 5 17 − 4 ) : 7 0 = ( 5 2 − 4 ) : 1 = 21
c) 295 − ( 31 − 2 2 .5 ) 2 = 295 − 11 2 = 174
a 20:2^2 -5^9:5^8
= 20:4 - 5^1
=5-5
=0
a) 20 : 2 2 − 5 9 : 5 8 = 5 − 5 = 0.
b) ( 5 19 : 5 17 − 4 ) : 7 0 = ( 5 2 − 4 ) : 1 = 21.
c) 295 − ( 31 − 2 2 .5 ) 2 = 295 − 11 2 = 174.
;)
Bài2:Thựchiệnphéptính:
a. (519 : 517 + 3) : 7 b. 79 : 77 – 32 + 23.52 c. 1200 : 2 + 62.21 + 18 d. 59 : 57 + 70 : 14 – 20
| e. 32.5 – 22.7 + 83 f. 59 : 57 + 12.3 + 70 g. 5.22 + 98:72 h. 311 : 39 – 147 : 72 | i. 295 – (31 – 22.5)2 j. 151 – 291 : 288 + 12.3 k. 238 : 236 + 51.32 - 72 l. 791 : 789 + 5.52 – 124 m. 4.15 + 28:7 – 620:618 |
a: \(\left(5^{19}:5^{17}+3\right):7=\left(5^2+3\right):7=4\)
b: \(7^9:7^7-3^2+2^3\cdot5^2\)
\(=7^2-3^2+8\cdot25\)
=49-9+200
=240
c: \(1200:2+6^2\cdot2^1+18\)
\(=600+72+18\)
=690
3.22 nha :)))
a) 232 - (581 + 132 - 331)
= 232 - 581 - 132 + 331
= (232 - 132) - (581 - 331)
= 100 - 250
= - (250 – 100)
= - 150
b) [12 + (-57)] - [- 57 - (-12)]
= (12 – 57) – (- 57 + 12)
= 12 - 57 + 57 - 12
= (12 – 12) + (57 – 57)
= 0 + 0
= 0
a) 232 - (581 + 132 - 331)
= 232 - 581 - 132 + 331
= (232 - 132) - (581 - 331)
= 100 - 250
= - (250 – 100)
= - 150
b) [12 + (-57)] - [- 57 - (-12)]
= (12 – 57) – (- 57 + 12)
= 12 - 57 + 57 - 12
= (12 – 12) + (57 – 57)
= 0 + 0
= 0
Tham khảo :
a) 232 - (581 + 132 - 331)
= 232 - 581 - 132 + 331
= (232 - 132) - (581 - 331)
= 100 - 250 = -150
b) [12 + (-57)] - [-57 - (-12)]
= 12 - 57 + 57 - 12
= (12 - 12) + (57 - 57)
= 0
Giúp mình với nhưng làm hết đc ko ạ
a) (519 : 517 + 3) : 7 b) 79 : 77 – 32 + 23.52 c) 1200 : 2 + 62.21 + 18 d) 59 : 57 + 70 : 14 – 20 e) 32.5 – 22.7 + 83 f) 59 : 57 + 12.3 + 70 g) 151 – 291 : 288 + 12.3 h) 238 : 236 + 51.32 - 72 i) 791 : 789 + 5.52 – 124 j) 4.15 + 28:7 – 620:618 k) (32 + 23.5) : 7 l) 1125 : 1123 – 35 : (110 + 23) – 60 m) 520 : (515.6 + 515.19) |
a, = (5^2 +3) : 7
= (25 +3) :7
= 28 : 7
= 4
a: \(=\left(5^2+3\right):7=28:7=4\)
b: \(=7^2-3^2+8\cdot25\)
=49-9+200
=240
d) 59 : 57 + 70 : 14 – 20
= 59-7 + 70 : 14 -20
= 52 + 70 : 14 - 20
= 25 + 70 : 14 - 20
= 25 + 5 - 20
= 30 - 20
= 10
e) 32.5 – 22.7 + 83
= 9.5 - 4.7 + 83
= 45 - 28 + 83
= 156