4 . 120 + [45 : 9 +15 . (x + 1) = 500
4 . 120 + [ 45 : 9 + 15 . ( X + 1 ) = 500
=>480 + [ 5 + 15 . (x + 1) = 500
15 . ( x + 1 )=500 - 480 - 5 = 15
x + 1 =15 : 15 =1
x =1 - 1
x = 0
vay x =0
k nha
tìm x biết
a,x\2008 - 1\10 -1\15 -1\21 - ...-1\120 = 5\8
b,7\x + 4\5*9 + 4\9*13 + 4\ 13*17 +...+4\41*45=29\45
tìm x :
4.120+[45:9+15-(x+1)]=500
4.120+[45:9+15-(x+1)]=500
480+[45:9+15-(x+1)]=500
45:9+15-(x+1)=500-480
45:9+15-(x+1)=20
5+15-(x+1)=20
20-(x+1)=20
x+1=20-20
x+1=0
x=0-1
x=-1
=>4.120+[45:9+15-(x+1)]=500
=>480+[45:9+15-(x+1)]=500
=>45:9+15-(x+1)=500-480
=>45:9+15-(x+1)=20
=>5+15-(x+1)=20
=>20-(x+1)=20
=>x+1=20-20
=>x+1=0
=>x=0-1
=> x=-1
Tìm x biết 4.120+[45:9+15(x+1)]=500
4.120+[45:9+15(x+1)]=500
=>480+[5+15(x+1)]=500
=>5+15(x+1)=20
=>15(x+1)=15
=>x+1=1
=>x=0
4.120+[45:9+15(x+1)]=500
480+[5+15x+15]=500
480+5+15x+15=500
500+15x=500
15x=0
x=0
x/2008-1/10-1/15-1/21-............-1/120=5/8
b, 7/x+4/5.9+4/9.13+4/13.17+......+4/41/ 45=29/45
Tim X
1) 5x = 120 : 2
2) 3x +27 + 45
3) 73 + x - 122 = 234 : 2
4) 32 - 2 ( x - 1 ) = 12
5)3 ( x + 1 ) - 15 = 36
6) 32 - ( 4x - 16 ) = 21
7) 13 x - 3x = 500
8) 9x + x - 35 = 68
Mn giup em nha, em can gap!
1) 5x = 120 : 2
5x = 60
x = 60 : 5
x = 12.
2) 3x + 27 = 45
3x = 45 - 27
3x = 18
x = 18 : 3
x = 6.
3) 73 + x - 122 = 234 : 2
73 + x - 122 = 117
73 + x = 117 + 122
73 + x = 239
x = 239 - 73
x = 166.
4) 32 - 2 ( x - 1 ) = 12
2 ( x - 1 ) = 32 - 12
2 ( x - 1 ) = 20
x - 1 = 20 : 2
x - 1 = 10
x = 10 + 1
x = 11.
5) 3 ( x + 1 ) - 15 = 36
3 ( x + 1 ) = 36 + 15
3 ( x + 1 ) = 51
x + 1 = 51 : 3
x + 1 = 17
x = 17 - 1
x = 16.
6) 32 - ( 4x - 16 ) = 21
4x - 16 = 32 - 21
4x - 16 = 11
4x = 11 + 16
4x = 27
x = 27 : 4
x = 6,75.
7) 13x - 3x = 500
( 13 - 3 )x = 500
10x = 500
x = 500 : 10
x = 50.
8) 9x + x - 35 = 68
9x + 1x - 35 = 68
9x + 1x = 68 + 35
9x + 1x = 103
( 9 + 1 )x = 103
10x = 103
x = 103 : 10
x = 10,3.
1) 5x = 120 : 2
5x = 60
x = 60 : 5
x = 12.
2) 3x + 27 = 45
3x = 45 - 27
3x = 18
x = 18 : 3
x = 6.
3) 73 + x - 122 = 234 : 2
73 + x - 122 = 117
73 + x = 117 + 122
73 + x = 239
x = 239 - 73
x = 166.
4) 32 - 2 ( x - 1 ) = 12
2 ( x - 1 ) = 32 - 12
2 ( x - 1 ) = 20
x - 1 = 20 : 2
x - 1 = 10
x = 10 + 1
x = 11.
5) 3 ( x + 1 ) - 15 = 36
3 ( x + 1 ) = 36 + 15
3 ( x + 1 ) = 51
x + 1 = 51 : 3
x + 1 = 17
x = 17 - 1
x = 16.
6) 32 - ( 4x - 16 ) = 21
4x - 16 = 32 - 21
4x - 16 = 11
4x = 11 + 16
4x = 27
x = 27 : 4
x = 6,75.
7) 13x - 3x = 500
( 13 - 3 )x = 500
10x = 500
x = 500 : 10
x = 50.
8) 9x + x - 35 = 68
9x + 1x - 35 = 68
9x + 1x = 68 + 35
9x + 1x = 103
( 9 + 1 )x = 103
10x = 103
x = 103 : 10
x = 10,3.
Bài 1 . Tìm X
a) 7/15 < X/40 < 8/15 ( phân số )
b) X - 140 : 35 = 270
c) 180 - ( X - 45 ) : 2 = 120
d) ( X - 2 ) x 3 - 270 : 45 = 120
e) 3,8 : ( X - 1,05 ) = 19/9 : 1/3 ( phân số )
f) 2 - ( 43/8 + X - 168/24 ) : 38/3 = 0
Tim x
1) 5x = 120 : 2
2) 3x + 27 = 45
3) 73 + x - 122 = 234 : 2
4) 32 - 2 ( x -1 ) = 12
5) 3 ( x + 1 ) - 15 = 36
6) 21 - ( 4x - 16 ) = 21
7)13 x - 3x = 500
8) 9x + x - 35 = 65
Giup e nha, em can gap
a) 5x = 120 : 2
5x = 60
x = 60 : 5
x = 12
b) 3x + 27 = 45
3x = 45 - 27
3x = 18
x = 18 : 3
x = 6
c) 73 + x - 122 = 234 : 2
73 + x - 122 = 117
73 + x = 117 + 122
73 + x = 239
x = 239 - 73
x = 166
d) 32 - 2(x - 1) = 12
2(x - 1) = 32 - 12
2(x - 1) = 20
x - 1 = 20 : 2
x - 1 = 10
x = 10 + 1
x = 11
e) 3(x + 1) - 15 = 36
3(x + 1) = 36 + 15
3(x + 1) = 51
x + 1 = 51 : 3
x + 1 = 17
x = 17 - 1
x = 16
f) 21 - (4x - 16) = 21
4x - 16 = 21 - 21
4x - 16 = 0
4x = 0 + 16
4x = 16
x = 16 : 4
x = 4
g) 13x - 3x = 500
10x = 500
x = 500 : 10
x = 50
h) 9x + x - 35 = 65
10x - 35 = 65
10x = 65 + 35
10x = 100
x = 100 : 10
x = 10
1/15+4/30+9/45+16/60+25/75+36/90+49/105+64/120+81/135
\(=\dfrac{1}{15}+\dfrac{2}{15}+\dfrac{3}{15}+...+\dfrac{9}{15}\)
\(=\dfrac{1+2+3+...+9}{15}\)
\(=\dfrac{45}{15}=3\)