( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10 ) = 62
tìm x biết : ( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10 ) = 62
(x+1)+(x+4)+(x+7)+(x+10)=62
=>4x+22=62
=>4x=62-22
=>4x=40
=>x=10
t tôi nha bn
( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10 ) = 62
4x+ (1+4+7+10)=62
4x+22=62
4x=62-22
4x=40
x=40:4
x=10
1. tìm x
(x+1)+(x+4)+(x+7)+(x+10)=62
(x+1)+(x+4)+(x+7)+(x+10)=62
( x + x + x + x ) + ( 1 + 4 + 7 + 10 ) = 62
4x + 22 = 62
4x = 62 - 22
4x = 40
x = 40 : 4
x = 10
(x + 1) + (x + 4) + (x + 7) + (x + 10) = 62
x + 1 + x + 4 + x + 7 + x + 10 = 62
4x + 22 = 62
4x = 40
=> x = 40 / 10 = 4
tìm x biết: (x+1)+(x+4)+(x+7)+(x+10)=62
\(\left(x+1\right)+\left(x+4\right)+\left(x+7\right)+\left(x+10\right)=62\)
\(\Rightarrow x+1+x+4+x+7+x+10=62\)
\(\Rightarrow4x+22=62\)
\(\Rightarrow4x=40\)
\(\Rightarrow x=10\)
tìm X
X+X+X+X+X =100
X+X+X+X *5 = 200
(X+1) + (X+4) +(X+7) + (X+10) =62
\(x\) + \(x\) + \(x\) + \(x\) = 100
\(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\)1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1 = 100
\(x\) \(\times\) ( 1 + 1 + 1 + 1 + 1 ) = 100
\(x\) \(\times\) 5 = 100
\(x\) = 100 : 5
\(x\) = 20
\(x\) + \(x\) + \(x\) + \(x\) \(\times\) 5 = 200
\(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\)1 + \(x\) \(\times\) 5 = 200
\(x\) \(\times\) ( 1 + 1 + 1 + 5) = 200
\(x\) \(\times\) 8 = 200
\(x\) = 200 : 8
\(x\) = 25
(\(x\) + 1) + (\(x\) + 4) + ( \(x\) + 7) + (\(x\) + 10) = 62
\(x\) + 1 + \(x\) + 4 + \(x\)+ 7 + \(x\) + 10 = 62
( \(x\) + \(x\) + \(x\) + \(x\) ) + ( 1 + 4 + 7 + 10) = 62
( \(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1) + 22 = 62
\(x\) \(\times\) ( 1 + 1 + 1 + 1) + 22 = 62
\(x\) \(\times\) 4 + 22 = 62
\(x\) \(\times\) 4 = 62 - 22
\(x\) \(\times\) 4 = 40
\(x\) = 40 : 4
\(x\) = 10
+ + + = 100
1 + 1 + 1 + 1 + 1 = 100
( 1 + 1 + 1 + 1 + 1 ) = 100
5 = 100
= 100 : 5
= 20
+ + + 5 = 200
1 + 1 + 1 + 5 = 200
( 1 + 1 + 1 + 5) = 200
8 = 200
= 200 : 8
= 25
( + 1) + ( + 4) + ( + 7) + ( + 10) = 62
+ 1 + + 4 + + 7 + + 10 = 62
( + + + ) + ( 1 + 4 + 7 + 10) = 62
( 1 + 1 + 1 + 1) + 22 = 62
( 1 + 1 + 1 + 1) + 22 = 62
4 + 22 = 62
4 = 62 - 22
4 = 40
= 40 : 4
= 10
tìm x
a, x2 + x = 0
b, (x-1)x+2 = (x-1)x+4
c, 1/4. 2/6. 3/8. 4/10. 5/12..... 30/62. 31/64=2x
d, x-1/ x+5= 6/7
e, x2/ 6= 24/25
g, x-2/ x-1= x+4/ x+7
a) x2 + x = 0
=> x( x+ 1 ) = 0
=> x = 0
hoặc x = -1
b) b, (x-1)x+2 = (x-1)x+4
=> x + 2 = x + 4
=> 0x = 2 ( ktm)
Vậy ko có giá trị x nào thoả mãn đk
d) Ta có: x-1/x+5 = 6/7
=>(x-1).7 = (x+5).6
=>7x-7 = 6x+ 30
=> 7x-6x = 7+30
=> x = 37
Vậy x = 37
e, x2/ 6= 24/25
=> x2 . 25 = 6 . 24
⇒
Vậy
g, x-2/ x-1= x+4/ x+7
a) Tính bằng hai cách:
36 x (7 + 3);
207 x (2 +6)
b) Tính bằng hai cách (theo mẫu):
Mẫu: 38 x 6 + 38 x 4 = ?
Cách 1: 38 x 6 + 38 x 4 = 228 + 152 = 380
Cách 2: 38 x 6 + 38 x 4 = 38 x (6 + 4) = 38 x 10 = 380
5 x 38 + 5 x 62;
135 x 8 + 135 x 2
a) 36 x (7 + 3) = ?
Cách 1: 36 x (7 + 3)
= 36 x 10 = 360
Cách 2: 36 x (7 + 3)
= 36 x 7 + 36 x 3 = 360
+) 207 x (2 +6) =?
Cách 1: 207 x (2 +6)
= 207 x 8 = 1656
Cách 2: 207 x (2 +6)
= 207 x 2 + 207 x 6 = 1656
b) 5 x 38 + 5 x 62 =?
Cách 1: 5 x 38 + 5 x 62
= 190 + 310 = 500
Cách 2: 5 x 38 + 5 x 62
= 5 x (38 +62) = 5 x 100 = 500
+) 135 x 8 + 135 x 2 =?
Cách 1: 135 x 8 + 135 x 2
= 1080 + 270 = 1350
Cách 2: 135 x 8 + 135 x 2
= 135 x (8 + 2) = 1350
Nói thêm: Nếu tính theo cách 1 thì nhanh hơn.
Tính và so sánh giá tri của biểu thức:
(3 +5) x 4 và 3 x 4 + 4 x 5
Từ kết quả so sánh, nêu cách nhân một tổng với một số.
(x-1)x+2=(x-1)x+4
1/ 4 . 2/6 . 3/8 . 4/10 . 5/15 .... 30/62 . 31/64= 2x
a) Ta có: \(\left(x-1\right)^{x+2}-\left(x-1\right)^{x+4}=0\)
\(\Leftrightarrow\left(x-1\right)^x\cdot\left(x-1\right)^2-\left(x-1\right)^x\cdot\left(x-1\right)^4=0\)
\(\Leftrightarrow\left(x-1\right)^{x+2}\cdot\left[1-\left(x-1\right)^2\right]=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-1=1\\x-1=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\\x=0\end{matrix}\right.\)
b) Ta có: \(\dfrac{1}{4}\cdot\dfrac{2}{6}\cdot\dfrac{3}{8}\cdot\dfrac{4}{10}\cdot\dfrac{5}{15}\cdot...\cdot\dfrac{30}{62}\cdot\dfrac{31}{64}=2x\)
\(\Leftrightarrow2x=\dfrac{1}{64}\)
hay \(x=\dfrac{1}{128}\)
Tìm x biết:
a) \((x-7)^{x+1}-(x-7)^{x+11}=0\)
b) \((x-1)^{x+2}=(x-1)^{x+4}\)
c) \(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}.\frac{4}{10}.\frac{5}{12}...\frac{30}{62}.\frac{31}{64}=2^x\)
Quên rùi!!!
1/4 x 2/6 x3/8 x 4/10 x 5/12 x....x 30/62 x 31/64=2n. Tìm n
<=> \(\frac{1.2.3....31}{4.6.8....64}=2^n\Rightarrow\frac{1.2.3....30.31}{2\left(2.3.4.5...31\right).32}=2^n\Leftrightarrow\frac{1}{2.32}=2^n\Leftrightarrow\frac{1}{2^6}=2^n\)
=> 2^6.2^n = 1
=> 2^ (n + 6 ) = 2^0
=> n+ 6 = 0
=> n = - 6
\(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}....\frac{31}{64}=\frac{1.2.3....31}{4.6.8....64}=\frac{1.2.3....31}{2.3.2.4....2.32}=\frac{1.2.3....31}{2^{30}.\left(3.4....32\right)}=\frac{2}{2^{30}.32}=\frac{1}{2^{34}}=2^{-34}=2^n=>n=-34\)
2^n × 2³¹ = \(\dfrac{ }{ }\)2/4×4/6×6/8×...×62/64
2^n×2³¹=1/32=2^-5
2^n=2^-5 ÷ 2³¹=2^-36
=>n=-36