(x+15)-125=57 : 55
720: [ 41-( 2x - 5 )= 23 .5
27- 3 ( x + 4 ) =23
2015x . 53 = 125
5) (34-53+28)-(34-53-21). (15-57+38)-(15+21+38)
(23-15+38)-(-47-15+23). (53-37+19)-(19+53-25)
(125+49-37)-(49+125-228). (221+23-58)-(58+221+23)
Úp nha
(34 - 53 + 28) - (34 - 53 - 21)
= 34 - 53 + 28 - 34 + 53 + 21
= (34 - 34) - (53 - 53) + (28 + 21)
= 0 - 0 + 49
= 49
(23 - 15 + 38) - (-47 - 15 + 23)
= 23 - 15 + 38 + 47 + 15 - 23
= (23 - 23) - (15 - 15) + (38 + 47)
= 85
(125 + 49 - 37) - (49 + 125 - 228)
= 125 + 49 - 37 - 49 - 125 + 228
= (125 - 125) + (49 - 49) - (37 - 228)
= -(-191) = 191
Tìm x
23+3x=125
41-(2x-5)=18
23+3x=125
3x=125-23
3x= 102
x= 102:3
x= 34
41-(2x-5)=18
2x-5=41-18
2x-5=23
2x=23+5
2x=28
x=28:2
x=14
720 ; {41-(2x - 5) } = 23.5
2x.4=128
x15=x
(2x + 1)3=125
720:[41-(2x-5)]=2^3.5
720:[41-2x+5]=40
[41+5-2x]=720:40
46-2x=18
2x=46-18
2x=28
x=14
a, 2x.4=128
2x=128:4
2x=32
2x=25
x=5
Vay x=5
b, x15=x
x=1
Vay x=1
Tìm x thuộc n
x^6 : x^3 =125
(2x-15)^4=(2x-15)^3
3^x+2-5.3^x=36
2.2^2x+4^3.4^x=1056
7.4^x-1+4^x+1=23
x6:x3=125
x6-3=125
x3=125
x3=53
x=5
vậy x=5
[(10-x).2+51]:3-2=3 (X-12)-15=20-(17+x) 720-[41-(2x-5)]=2( mũ 3). 5 | (2x là 2 nhân x,chấm là dấu nhân X-{57-[42+(-23-x)]}=13-{47+[25-(32-x)]}
a: \(\left[\left(10-x\right)\cdot2+51\right]:3-2=3\)
=>\(\left[2\left(10-x\right)+51\right]:3=5\)
=>\(\left[2\left(10-x\right)+51\right]=15\)
=>\(2\left(10-x\right)=15-51=-36\)
=>10-x=-36/2=-18
=>\(x=10-\left(-18\right)=10+18=28\)
b: \(\left(x-12\right)-15=20-\left(17+x\right)\)
=>\(x-12-15=20-17-x\)
=>\(x-27=3-x\)
=>\(2x=30\)
=>\(x=\dfrac{30}{2}=15\)
c: \(720-\left[41-\left(2x-5\right)\right]=2^3\cdot5\)
=>\(720-\left[41-2x+5\right]=8\cdot5=40\)
=>\(\left[41-2x+5\right]=720-40=680\)
=>-2x+46=680
=>-2x=680-46=634
=>\(x=\dfrac{634}{-2}=-317\)
Tim x : 1440:[41-(2x-5)]=24.3 ;5.[225-(x-10)]-125=0
Tìm X :
a. 23 . ( 42 - x ) = 46
b. 7 x - 8 = 41
c. 125 -5 ( x +3 ) = 15
dấu chấm là nhân
nhớ trình bày cách làm !
a. 23 . ( 42 - x ) = 46
42 - x = 46 : 23
42 - x = 2
x = 42 - 2
x = 40
b. 7x - 8 = 41
7x = 41 + 8
7x = 49
x = 49 : 7
x = 7
c. 125 - 5(x + 3) = 15
5(x + 3) = 125 - 15
5(x + 3) = 110
x + 3 = 110 : 5
x + 3 = 22
x = 22 - 3
x = 19
a) 23 . ( 42 - x) = 46 => 42 - x = 46 : 23 = 2
=> x = 42 - 2 = 40
b) 7x - 8 = 41 => 7x = 41 + 8 = 49 => x = 49 : 7 = 7
c) 125 - 5.(x+3) = 15 => 5.(x+3) = 125 - 15 = 110 => x + 3 = 110 : 5 =22
=> x = 22 - 3 = 19
Bài 2: (2,5 điểm) Tìm x, biết:
a) 23 + 3x = 125 b) 70 – 5.(x - 3)= 45 c) 20 + 5x = 57:55
a)23+3 𝑥 =125 | b) 70 – 5.(𝑥 - 3)= 45 | c) 20 + 5 𝑥 = 57:55
3 𝑥 +23=125 | 70−5 𝑥 +15=45 | 5 𝑥 +20=5755
𝑥=34 | 𝑥=8 | 𝑥=−104
275
a: \(\Leftrightarrow3x=102\)
hay x=34
Giải phương trình:
1) (3x-1)^2-5(2x+1)^2+96x-3)(2x+1)=(x-1)^2
2) (x+2)^3-(x-2)^3=12(x-1)-8
3) x-1/4-5-2x/9=3x-2/3
4) 25x-655/95-5(x-12)/209=[89-3x-2(x-13)/5]/11
5) 29-x/21+27-x/23+25-x/25+23-x/27=-4
6) x-69/30+x-67/32=x-63/36+x-61/38
7)x+117/19+x+4/28+x+3/57=0
8) 59-x/41+57-x/43+2=x-55?45+x-53/47-2
9) Cho phương trình: mx+x-m^2=2x-2 (x là ẩn). Tìm m để phương trình:
a) Có nghiệm duy nhất
b) Vô số nghiệm
c) Vô nghiệm