Lời giải:
$(x-7)^{x-1}-(x-7)^{x+11}=0$
$\Rightarrow (x-7)^{x-1}[1-(x-7)^{12}]=0$
$\Rightarrow (x-7)^{x-1}=0$ hoặc $1-(x-7)^{12}=0$
Nếu $(x-7)^{x-1}=0$
$\Rightarrow x-7=0\Rightarrow x=7$.
Nếu $1-(x-7)^{12}=0$
$\Rightarrow (x-7)^{12}=1\Rightarrow x-7=1$ hoặc $x-7=-1$
$\Rightarrow x=8$ hoặc $x=6$
Vậy.............
2/7 : 1/4 - 1/7
7/11 x 0 + 5/9 : 1/2
( 3/7 + 1/4 ) : 3/4
4/3 x 1/2 + 7/2 : 1/4
1. Tính
a) 5/7 x 4 : 5/9
b) 8 x 2/3 : 1/2
c) 6 : 3/5 - 7/6 x 6/7
21/5 x 10/11 + 57/11
2. Tìm x
a) 35/9 : x = 35/6
b) (1/1x2 + 1/2x3 + 1/3x4 +1/4x5 +1/5x6) x 10- x = 0
a,\(\dfrac{1}{7}\text{x}\dfrac{2}{7}+\dfrac{1}{7}\text{x}\dfrac{5}{7}+\dfrac{6}{7}\) b,\(\dfrac{6}{11}\text{x}\dfrac{4}{9}+\dfrac{6}{11}\text{x}\dfrac{7}{9}-\dfrac{6}{11}\text{x}\dfrac{2}{9}\)
c, \(\dfrac{4}{25}\text{x}\dfrac{5}{8}\text{x}\dfrac{25}{4}\text{x}24\)
Bài : Tìm x thuộc Z , biết :
a) 15 - 5. | x+4 | =-12 - 3
b) ( 4x - 8) . ( 7-x ) = 0
c) ( x^2 - 36) x ( x^2 + 5 ) =0
d) -3. ( x+7) -11 = 2.(x +5)
1 x2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 x 11 x 12 x 13 x 14 x 15 x 16
Tích này có bao nhiêu số 0?
1 x 2 + 2 x 4 + 4 x 7 + 7 x 11 + 11 x 16 + 16 x 22 =
Tình nhanh
tìm x
a 6 x + 15x8=12.(19-x)
b 160-(35: x +3 )x15=15
c 2x - ( 1309:11-19)-2=0
d (x-7)x(2x-16)=0
giúp mk với
1 x 2 x 3 x 4 x 5 x 6 x 6 x 7 x 8 x 9 x 10 x 11 x 12 x 13 x 14 x 15 x 16 x 17 x 18 x 0 x 19 x 20 = ?
Đố các bạn bằng bao nhiêu ?
a.(x*2,4-4,2):x=1
b.1/1x3+1/3x5+1/5x7+...+1/x(x+2)
c.7/3+7/4-7/11 +5/7
5/3+5/9-5/11
