1+3+5+7+...+x=100 Tim x
tim x giup to voi 1+3+5+7+....+x =100
x = 100 : 5 - 1
x = 20 - 1
x = 19
Vậy x = 19
1 )Tim x, y thuoc Z
x + y = x.y
2) Tim x thuoc Z
(x + 1)+(x+3)+(x+5)+...+(x+99)=0(x-3)+(x-2)+(x-1)+...+10+11=11-12(x-5)+7(3-x)=530(x+2)-6(x-5)-24x=100x + y = x.y
=> xy - x - y = 0
=> (xy - x) - y + 1 = 1
=> x(y - 1) - (y - 1) = 1
=> (x - 1)(y - 1) = 1
=> x - 1 = y - 1 = 1 hoặc x - 1 = y - 1 = -1
=> x = y = 2 hoặc x = y = 0
Tim x biet
1/3×5+1/5×7+.....+1/(2x+1)(2x+3)=100/609
tim x biet
1) 23x-1=32
2) 4.52x=5^7-5^6
3) x3(x2-1)=0
4) x100=x48
5) x100=x
6) x100=x2
7) (x-2015)2105=1
8) 100(x-3).(x-2)=1
1) Tim x biet :
a) - 12 (x - 5) + 7 . (3 - x) = 5
b) 30 . (x + 2) - 6 . (x - 5) - 24x = 100
Tim x:
a, [x+1] + [x+2] + [x+3] + ... + [x+100] bang 206050
b, [1-3/10-x] : [19/20-1-2/5]
c, |2x-2| bang x+18
d, | |11-x| +9| - 7 bang 12
a, so sánh : 202^303 và 303^202 ;3^21 và 2^31
b, tim n sao cho : 50<2^n<100 ; 50<7^n<2500
c, tim x biết : 2^x*7=224 ; (3*x+5)^2=289 ; x*(x ^2)^3=x^5 ; 3^2*x+1 *11=2673
Nhiều quá
a)202303=(2023)101=8242408101
303^202=(302^2)^101=91204^101
Vì 824208^101>91204^101=>202^303>303^202
tim x :
A)219-7.(x.1)=100
B)(3x-6).3=34
C)3.2x=48
D)5.x2=180
a. 219-7.(x.1)=100
7.x=219-100
7x=119
x=119:7
x=17
b.(3x-6).3=34
3x-6=34:3
3x-6=33
3x-6=27
3x=27+6
3x=33
x=33:3
x=11
c.3.2x=48
2x=48:3
2x=16
2x=24
x=4
d. 5.x2=180
x2=180:5
x2=36
x2=62
x=6
a)219-7.(x.1)=100
7.(x.1) =219-100
7.(x.1) =119
(x.1) =119:7
(x.1) =17
x =17.1
x 17
b)(3x-6).3=3^4
(3x-6).3=81
(3x-6) =81:3
(3x-6) =27
3x =27+6
3x =33
x =33:3
x =11
c)3.2^x=48
2^x=48:3
2^x=16
2^x=2^4
Suy ra x=4
d)5.x^2=180
x^2=180:5
x^2=36
x^2=6^2
Suy ra x=6
tim x
(x+1)+(x+3)+(x+5)=100
X x 3 + 1 + 3 + 5 = 100
X x 3 = 100 - 5 - 3 - 1
X x 3 = 91
Bạn xem lại đề nhé
=D
( X + 1 ) + ( X + 3 ) + ( X + 5 ) = 100
X + 1 + X + 3 + X + 5 = 100
( X x 3 ) + ( 1 + 3 + 5 ) = 100
( X x 3 ) + 9 = 100
X x 3 = 100 - 9
X x 3 = 91
X = 91 : 3
X = 91/3
Đề bài sai rồi bạn
(x+1)+(x+3)+(x+5)=100
3x + ( 1 + 3 + 5 ) = 100
3x + 9 = 100
3x = 100 - 9
3x = 91
x = 91 : 3
x = 30,33
Vậy x = 30,33