Tìm X :
a) x – 425 = 625
b) x – 103 = 99
1.Tính
23 x 46 =
34 x 10 =
54 x 46 =
17 x 35 =
19 x 30 =
2.Tìm x
a) x : 11 = 35
b) x : 11 = 87
c) x - 425 = 625
d) x - 103 = 99
e) x + 527 = 1892
f) X x 5 = 1085
1. Tính
23 x 46 = 1058
34 x 10 = 340
54 x 46 = 2484
17 x 35 = 595
19 x 30 = 570
2 Tìm X :
a) X : 11 = 35 b) X : 11 = 87 c) X - 425 = 625
X = 35 x 11 X = 87 x 11 X = 625 + 425
X = 385 X = 957 X = 1050
Vậy X = 385 Vậy X = 957 Vậy X = 1050
d) X - 103 = 99 e) X + 527 = 1892 f) X x 5 = 1085
X = 99 + 103 X = 1892 - 527 X = 1085 : 5
X = 202 X = 1365 X = 217
Vậy X = 202 Vậy X = 1365 Vậy X = 217
1. Tính
23 x 46 = 1058
34 x 10 = 340
54x 46 =2484
17 x 35 = 595
19 x 30 = 570
2.Tìm X
a) X : 11 = 35
X = 35 x 11
X = 385
b) X : 11 = 38
X = 87 x 11
X = 957
c) X - 425 = 625
X = 625 + 425
X = 1050
d) X - 103 = 99
X = 103 + 99
X = 202
e) X + 527 = 1892
X = 1892 - 527
X = 1362
f) X x 5 = 1058
X = 1058 :5
X = 217
Tìm x biết:
\(\frac{x-999}{99}+\frac{x-896}{101}+\frac{x-789}{103}=6.\)
Ta có: \(\frac{x-999}{99}+\frac{x-896}{101}+\frac{x-789}{103}=6\)
\(\Rightarrow\left(\frac{x-999}{99}-1\right)+\left(\frac{x-896}{101}-2\right)+\left(\frac{x-789}{103}-3\right)=6-6\)
\(\Rightarrow\frac{x-1098}{99}+\frac{x-1098}{101}+\frac{x-1098}{103}=0\)
\(\Rightarrow\left(x-1098\right).\left(\frac{1}{99}+\frac{1}{101}+\frac{1}{103}\right)=0\)
Vì \(\frac{1}{99}+\frac{1}{101}+\frac{1}{103}\ne0\)
=> x - 1098 = 0
=> x = 0 + 1098
=> x = 1098
Vậy x = 1098
tìm x biết:
\(\frac{x-1}{99}-\frac{x+1}{101}+\frac{x-2}{98}-\frac{x+2}{102}+\frac{x-3}{97}-\frac{x+3}{103}+\frac{x-4}{96}-\frac{x+4}{104}=0\)
tìm x biết:
\(\frac{x-1}{99}-\frac{x+1}{101}+\frac{x-2}{98}-\frac{x+2}{102}+\frac{x-3}{97}-\frac{x+3}{103}+\frac{x-4}{96}-\frac{x+4}{104}=0\)
\(\frac{x-1}{99}-\frac{x+1}{101}+\frac{x-2}{98}-\frac{x+2}{102}+\frac{x-3}{97}-\frac{x+3}{103}+\frac{x-4}{96}-\frac{x+4}{104}=0\)
\(\Rightarrow\frac{x-1}{99}-1-\frac{x+1}{101}+1+\frac{x-2}{98}-1-\frac{x+2}{102}+1+\frac{x-3}{97}-1-\frac{x+3}{103}+1+\frac{x-4}{96}-1-\frac{x+4}{104}+1=0\)
\(\Rightarrow\frac{x-100}{99}-\frac{x-100}{101}+\frac{x-100}{98}-\frac{x-100}{102}+\frac{x-100}{97}-\frac{x-100}{103}+\frac{x-100}{96}-\frac{x-100}{104}=0\)
\(\Rightarrow\left(x-100\right).\left(\frac{1}{99}-\frac{1}{101}+\frac{1}{98}-\frac{1}{102}+\frac{1}{97}-\frac{1}{103}+\frac{1}{96}-\frac{1}{104}\right)=0\)
Vì \(\frac{1}{99}>\frac{1}{101};\frac{1}{98}>\frac{1}{102};\frac{1}{97}>\frac{1}{103};\frac{1}{96}>\frac{1}{104}\)
\(\Rightarrow\frac{1}{99}-\frac{1}{101}+\frac{1}{98}-\frac{1}{102}+\frac{1}{97}-\frac{1}{103}+\frac{1}{96}-\frac{1}{104}\ne0\)
\(\Rightarrow x-100=0\)
\(\Rightarrow x=100\)
Vậy \(x=100\)
\(\dfrac{x-1}{99}-\dfrac{x+1}{101}+\dfrac{x-2}{98}-\dfrac{x+2}{102}+\dfrac{x-3}{97}-\dfrac{x+3}{103}+\dfrac{x-4}{96}-\dfrac{x+4}{104}=0\)
<=> \(\dfrac{x-1}{99}-1-\dfrac{x+1}{101}-1+\dfrac{x-2}{98}-1-\dfrac{x-2}{102}-1+\dfrac{x-3}{97}-1-\dfrac{x+3}{103}-1+\dfrac{x-4}{96}-1-\dfrac{x+4}{104}=0\)
Tìm x biết:
a, x : 25 = 1205 : 5
b, 2018 – x = 425 +725
a, x : 25 = 1205 : 5
x : 25 = 241
x = 241 x 25
x = 6025
b, 2018 – x = 425 +725
2018 – x = 1150
x = 2018 – 1150
x = 868
(99-x)/101+(97-x)/103+(95-x)/105+(93-x)/107=-4
giải phương trình ( x-999)/99 +( x -896)/101 + ( x-789)/103=6
\(\dfrac{x-999}{99}+\dfrac{x-896}{101}+\dfrac{x-789}{103}=6\)
\(\Leftrightarrow\dfrac{x-999}{99}-1+\dfrac{x-896}{101}-2+\dfrac{x-789}{103}-3=0\)
\(\Leftrightarrow\dfrac{x-1098}{99}+\dfrac{x-1098}{101}+\dfrac{x-1098}{103}=0\)
\(\Leftrightarrow\left(x-1098\right)\left(\dfrac{1}{99}+\dfrac{1}{101}+\dfrac{1}{103}\right)=0\)
Mà \(\dfrac{1}{99}+\dfrac{1}{101}+\dfrac{1}{103}>0\)
\(\Rightarrow x-1098=0\Leftrightarrow x=1098\)
Vậy x = 1098
\(\dfrac{x-999}{99}+\dfrac{x-896}{101}+\dfrac{x-789}{103}=0\)
⇔\(\dfrac{\left(x-999\right)\cdot10403+\left(x-896\right)10197+\left(x-789\right)\cdot9999}{1029897}=\dfrac{6\cdot1029897}{1029897}\)
⇔\(10403x-10392597+10197x-9136512+9999x-7889211=6179382\)⇔\(10403x+10197x+9999x=6179382+10392597+9136512+7889211\)
⇔\(30599x=33597702\)
⇔\(x=\dfrac{33597702}{30599}\)
⇔\(x=1098\)
Vậy x =1098 là nghiệm của phương trình
giúp với mọi người ơi
1.TÍNH:
A.=1-2+3-4+...-98+99
B=1-4+7-10+...-100+103
2.TÌM CÁC SỐ NGUYÊN X,Y BIẾT:
a) (x-1) . (y+2)=5
b) x. (y-5)=-12
Bài 1:Tính tổng
A . 1+(-2)+3+(-4)+...........19+(-20)
B.1-2+3-4+...........99-100
C.1+2-3-4+...........+97+98-99-100
Bài 2:Tìm số nguyên x
-2x-(x-17)=34-(-x+25)
103-57:[-2.(2x-1)2-(-9)0]
1)
A) 1+ (-2)+ 3+ (-4)+...+19+(-20)
<=> -1+(-1)+...+(-1)
có tất cả 10 số (-1) => -1*10= -10
B)1-2+3-4+...+99-100
<=> -1+(-1)+...+(-1)
Có tất cả 50 số (-1) =>-1*50=(-50)
Công thức tính tổng:
B1:SCSH:( cuối - đầu ) : khoảng cách + 1 = ? ( số hạng )
B2:Tổng:( cuối + đầu ) . SCSH : 2 = ?
Hk tốt
b)1-2+3-4+...........+99-100
=(1-2)+(3-4)+(5-6)+.................+(99-100)
=-1+(-1)+(-1)+.............+(-1) {có[(101.100):2]:2=2525(chữ số -1)
= -1.2525
= -2525
c)1+2-3-4+5+6-7-8+...............+97+98-99-100
=1+(2-3-4+5)+(6-7-8+9)+...........+(94-95-96+97)+(98-99-100)
=1+0+0+0+........................+0+(-297)
=1+(-207)
= -206