Tìm x , biết: x - 15= - 21
tìm x biết
\(\dfrac{x-2023}{6}\)\(+\dfrac{x-2023}{10}\)\(+\dfrac{x-2023}{15}\)\(+\dfrac{x-2023}{21}\)=\(\dfrac{8}{21}\)
\(\dfrac{x-2023}{6}+\dfrac{x-2023}{10}+\dfrac{x-2023}{15}+\dfrac{x-2023}{21}=\dfrac{8}{21}\)
\(\left(x-2023\right)\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}+\dfrac{1}{21}\right)=\dfrac{8}{21}\)
\(\left(x-2023\right).\dfrac{8}{21}=\dfrac{8}{21}\)
\(x-2023=1\)
\(x=2024\)
Vậy..............
\(...\Rightarrow\left(x-2023\right)\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}+\dfrac{1}{21}\right)=\dfrac{8}{21}\)
\(\Rightarrow\left(x-2023\right)\left(\dfrac{35+21+14+1}{210}\right)=\dfrac{8}{21}\)
\(\Rightarrow\left(x-2023\right).\dfrac{71}{210}=\dfrac{8}{21}\)
\(\Rightarrow\left(x-2023\right).\dfrac{71}{210}=\dfrac{8}{21}.\dfrac{210}{71}=\dfrac{80}{71}\)
\(\Rightarrow x-2023=\dfrac{80}{71}\Rightarrow x=\dfrac{80}{71}+2023=\dfrac{143713}{71}\)
\(\dfrac{x-2023}{6}+\dfrac{x-2023}{10}+\dfrac{x-2023}{15}+\dfrac{x-2023}{21}=\dfrac{8}{21}\)
\(\Leftrightarrow\left(x-2023\right).\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}+\dfrac{1}{21}\right)=\dfrac{8}{21}\)
\(\Leftrightarrow\left(x-2023\right).\left(\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}\right)=\dfrac{4}{21}\)
\(\Leftrightarrow\left(x-2023\right).\left(\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}+\dfrac{1}{6.7}\right)=\dfrac{4}{21}\)
\(\Leftrightarrow\left(x-2023\right).\left(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}\right)=\dfrac{4}{21}\)
\(\Leftrightarrow\left(x-2023\right).\left(\dfrac{1}{3}-\dfrac{1}{7}\right)=\dfrac{4}{21}\)
\(\Leftrightarrow x-2023=1\Leftrightarrow x=2024\)
tìm x biết 18/15>x>21/37
tìm x thuộc N, biết :
a) x - 105 : 21 = 15
b) ( x - 105 ) : 21 = 15
c) 315 + ( 125 - x ) = 435
a) x - 105 : 21 = 15
x - 5 = 15
=> x = 20
b) ( x - 105 ) : 21 = 15
x - 105 = 315
=> x = 420
c) 315 + ( 125 - x ) = 435
125 - x = 120
=> x = 5
a)x - 105 : 21 = 15
x - 5 =15
x =20
b) (x - 105) :21=15
x -105 =315
x =420
c) 315+ (125 - x ) =435
125 - x =-120
x =5
tìm x biết:
a,315+(125-x)=435
b,x:41=32
c,(x-105):21=15
d,x-105:21=15
,
a) \(315+\left(125-x\right)=435\)
\(\Leftrightarrow125-x=435-315\)
\(\Leftrightarrow125-x=120\)
\(\Leftrightarrow x=125-120\)
\(\Leftrightarrow x=5\)
b) \(x:41=32\)
\(\Leftrightarrow x=32\cdot41\)
\(\Leftrightarrow x=1312\)
c) \(\left(x-105\right):21=15\)
\(\Leftrightarrow x-105=15\cdot21\)
\(\Leftrightarrow x-105=315\)
\(\Leftrightarrow x=315+105\)
\(\Leftrightarrow x=420\)
d) \(x-105:21=15\)
\(\Leftrightarrow x-5=15\)
\(\Leftrightarrow x=15+5\)
\(\Leftrightarrow x=20\)
a, 315 + ( 125 - x ) = 435
( 125 - x) = 435 - 315
( 125 - x ) = 320
x = 320 - 125
x = 195
bạn văn quang long tính sai rồi 435-315=120 chứ
Tìm X biết:
1) X - 105 : 21 = 15
2) ( X - 105 ) : 21 = 15
3) ( 32 + X ) : 17 = X
4) 1818 : ( 6X - 37 ) = 18
1)\(x-105:21=15\)
\(x-5=15\)
\(x=15+5\)
\(x=20\)
Vậy \(x=20.\)
2)\(\left(x-105\right):21=15\)
\(\left(x-105\right)=15.21\)
\(x-105=315\)
\(x=315+105\)
\(x=420\)
Vậy \(x=412.\)
4)\(1818:\left(6x-37\right)=18\)
\(6x-37=1818:18\)
\(6x-37=101\)
\(6x=101+37\)
\(6x=138\)
\(x=138:6\)
\(x=23\)
Vậy \(x=23.\)
mk quên,còn phần 3) nữa:
3)\(\left(32+x\right):17=x\)
\(32+x=x.17\)
\(\Leftrightarrow x=2\)
Vậy \(x=2.\)
tìm x biết
x - 105 : 21 = 15
x - 105 : 21 = 15
x - 105 = 315
x =420
tk mk nhé
x - 105 ÷ 21 = 15
x - 5 = 15
x = 15 + 5
x = 20
tìm x biết ; [ -3x +21 ] [ 5 .| x | - 15 ] =0
[ -3x +21 ] [ 5 .| x | - 15 ] =0
<=> (-3x+21)=0 hoặc (5|x|-15)=0
<=> x=7 hoặc |x|=3
<=> x={7;-3;3}
Tìm số tự nhiên x, biết:
d) (x – 105) : 21 = 15
d) (x – 105) : 21 = 15
(x – 105) = 15. 21
(x – 105) = 315
x = 315+ 105
x = 420
Vậy x = 420
Tìm số tự nhiên x, biết:
b) x – 105 : 21 = 15
b) x – 105 : 21 = 15
x – 5 = 15
x = 15+5
x = 20
Vậy x = 20