tìm x biết : ( 2008 - x ) : 29 + 32 =100
Tìm x biết (2015 - x) :29 + 32 = 100
( 2015 - x ) : 29 + 32 = 100
( 2015 - x ) : 29 = 100 - 32
( 2015 - x ) : 29 = 68
2015 - x = 68 x 29
2015 - x = 1972
x = 2015 - 1972
x = 43
L i k e nha các bạn !!!
(2015-x):26=100-32
(2015-x):26=68
2015-x=68x26
2015-x=1768
x=2015-1768
x=247
Ta co :
(2015 - x):29+32=100
(2015-x):29 = 100 - 32
(2015-x):29 = 68
2015-x = 68 . 29
2015-x = 1972
x = 2015 - 1972
x =43
Tìm x:
a) (2009 - x) : 29 + 32 = 100.
b) (x - 2) x 3 - 270 : 45 = 120.
\(\left(2009-x\right):29+32=100\\ =>\left(2009-x\right):29=100-32=68\\ =>2009-x=68.29=1972\\ =>x=2009-1972=37\)
-
\(\left(x-2\right).3-270:45=120\\ =>3\left(x-2\right)-6=120\\ =>3\left(x-2\right)=120+6=126\\ =>x-2=126:3=42\\ =>x=42+2=44\)
Tìm x
a) ( x - 149 ) : 35 = 270
b) ( 2009 - x ) : 29 + 32 = 100
c) x + 472 = 918
#)Giải :
a)\(\left(x-149\right)\div35=270\)
\(\Leftrightarrow x-149=9450\)
\(\Leftrightarrow x=9599\)
\(a,(x-149):35=270\)
\(\Leftrightarrow x-149=9450\)
\(\Leftrightarrow x=9450+149=9599\)
Vậy x = 9599
\(b,(2009-x):29+32=100\)
\(\Leftrightarrow(2009-x):29=68\)
\(\Leftrightarrow2009-x=1972\)
\(\Leftrightarrow x=2009-1972=37\)
Vậy x = 37
\(c,x+472=918\)
\(\Leftrightarrow x=918-472=446\)
Vậy x = 446
a) (x - 149) : 35 = 270
x - 149 = 270 . 35
x - 149 = 9450
x = 9450 + 149
x = 9599
b) (2009 - x) : 29 + 32 = 100
(2009 - x) : 29 = 100 - 32
(2009 - x) : 29 = 68
2009 - x = 68 x 29
2009 - x = 1972
x = 2009 - 1972
x = 37
c) x + 172 = 918
x = 918 - 472
x = 446
Tìm x,biết:
a) 7/x + 4/5x9 + 4/9x13 + .....+ 4/41x45 = 29/45
b) x/2008 - (1/10 + 1/15 + 1/21 +..............+1/120) = 5/8
a) \(\frac{7}{x}+\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{41}-\frac{1}{45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\frac{8}{45}=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}=\frac{29}{45}-\frac{8}{45}\)
\(\Rightarrow\frac{7}{x}=\frac{7}{15}\)
\(\Rightarrow x=15\)
Vậy x = 15
b) \(\frac{x}{2008}-\left(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\right)=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-\left(\frac{2}{20}+\frac{2}{30}+\frac{2}{42}+...+\frac{2}{240}\right)=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-\left(\frac{2}{4.5}+\frac{2}{5.6}+\frac{2}{6.7}+...+\frac{2}{15.16}\right)=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-2\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+...+\frac{1}{15}-\frac{1}{16}\right)=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-2\left(\frac{1}{4}-\frac{1}{16}\right)=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-2.\frac{3}{16}=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}-\frac{3}{8}=\frac{5}{8}\)
\(\Rightarrow\frac{x}{2008}=\frac{5}{8}+\frac{3}{8}\)
\(\Rightarrow\frac{x}{2008}=1\)
\(\Rightarrow x=2008\)
Vậy x = 2008
_Chúc bạn học tốt_
bài 1 tính
a, 24 x 66 - 24 + 36 x 24
b, 29 x 173 - 29 x 72 -29
c, 1+5+10+15+...+55+60
d, 1x2+2x3+3x4 +...+18x19+19x20
bài 2 tìm x
a,106- ( x+ 7) =9
b, 2 x ( x+ 4) + 5 =65
c, (16x x -32) x 45=0
d, x+4 x x = 100 : 5
bài 2 tìm x
a,106- ( x+ 7) =9
x+7 = 106 - 9
x+7 = 107
x= 107 - 7
x=100
b, 2 x ( x+ 4) + 5 =65
2 x (x+4) = 65 - 5
2 x (x+4) = 60
x+4 = 60:2
x+4= 30
x= 30 - 4
x=26
c, (16x x -32) x 45=0
16 x X - 32 = 0: 45
16 x X - 32 =0
16 x X = 0 + 32
16 x X = 32
X= 32:16
X=2
d, x+4 x x = 100 : 5
X + 4 x X = 20
(1+4) x X = 20
5 x X = 20
X= 20:5
X=4
Bài 1:
a, 24 x 66 - 24 + 36 x 24
= 24 x (66-1+36)
= 24 x 101
= 24 x 100 + 24
= 2400+24
=2424
b, 29 x 173 - 29 x 72 - 29
= 29 x (173 - 72 -1)
= 29 x 100
= 2900
c, 1+5+10+15+...+55+60
= (5+60) x 6 + 1 (có 6 cặp)
= 65 x 6 + 1
= 390 +1 =391
d, D= 1 x 2 + 2 x 3 + 3 x 4 +...+18 x 19 + 19 x 20
3D= 1 x 2 x 3+ 2 x 3 x (4-1) + 3 x 4 x (5-2) +...+ 18 x 19 x (20 - 17) + 19 x 20 x (21-18)
3D= 1 x 2 x 3 - 1 x 2 x 3 + 2 x 3 x 4 - 2 x 3 x 4 +.... + 19 x 20 x 21 - 18 x 19 x 20
3D= 19 x 20 x 21 =7980
=> D= 7980:3=2660
Giúp tớ với .giải chi tiết cho minh cái bài ky mà
1 : Tìm các số tự nhiên x,y biết :
a, 4/x= y/45=12/15
2 Tính nhanh
F=75/100+18/21+19/32+1/4+3/21+13/32
3 : So sánh các phân số sau
2008/2009 với 2010/2011 ; 1999/2001 với 12/11 ;2007/2006 với 2006/2007 ; 101/100 với 100/101
x = 5 y = 36
( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 )
= 1 + 1 + 1 = 3
2008/2009 > 2010/2011 ; 1999/2001 < 12/11 ;2007/2006> 2006/2007 ; 101/100 >100/101
1.
x = 5
y = 36
2.
( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 ) = 1 + 1 + 1 = 3
3.
> ; < ; > ; >
x = 5 y = 36
( 18 / 21 + 3 / 21 ) + ( 19 / 32 + 13 / 32 ) + ( 75 / 100 + 1 / 4 )
= 1 + 1 + 1 = 3
2008/2009 > 2010/2011 ; 1999/2001 < 12/11 ;2007/2006> 2006/2007 ; 101/100 >100/101
[2009-x]:29+32=100
( 2009 - x ) : 29 + 32 = 100
( 2009 - x ) : 29 = 100 - 32
( 2009 - x ) : 29 = 68
( 2009 - x ) = 68 . 29
2009 - x = 1972
x = 2009 - 1972
x = 37
[2009 - x] : 29 =100-32
[2009-x] : 29 =68
2009-x =68x29
2009-x=1972
x=2009-1972
x=37
(2009-x):29+32=100
=>(2009-x):29=100-32
=>(2009-x):29=68
=>2009-x=68x29
=>2009-x=1972
=>x=2009-1972
=>x=37
(2009 - x ) : 29 +32 = 100
(2009-x) : 29 + 32 = 100
(2009-x): 29 = 68
2009-x = 68 x 29
2009 - x = 2001
x= 2009 - 2001
x=8
( 2009 - x ) : 29 + 32 = 100
( 2009 - x ) : 29 = 100 - 32
( 2009 - x ) : 29 = 68
2009 - x = 68 x 29
2009 - x = 1972
x = 2009 - 1972
x = 37
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