1 = 5
2 = 10
3 = 15
4 = 20
5 = ?????
1=5
2=10
3=15
4=20
5=?
1+4+7+10+...........+52+53-154
1 + 4 + 7 + 10 + ............ + 52 + 53 - 154 = 427
Đặt A=1+4+7+10+..........+52+53-154
Ta có: A=(1+4+7+............+52)+53-154
B
Ta có: B= (52+1)x18:2
=> B=477
Vậy A=477+53-154
=> A=530-154
=> A=376
Vậy tổng trên bằng 376
Bài 1: tìm x TRÌNH BÀY LUÔN
1) 2x+20=122
2) 26-2x=20
3) 5x+205=295
4) 75+12:x=81
5) 3x-7=14
6) 45:(12-x)=3
7) 172-2.(x-30)=94
8) (x+52)-27=54
9) 72:3(x-3)=6
10) 19-(4x+1)=10
1) \(x=51\)
2) \(x=3\)
3) \(x=18\)
4) \(x=2\)
5) \(x=7\)
(2006 x (154 - 52)) - 4012
[ 2006 x ( 154 - 52 )] - 4012
= [ 2006 x 102 ] - 4012
= 204612 - 4012
= 200600
2006 x 102 - 4012
= 204612 - 4012 = 200600
i) 10^2-60:(5^6:5^4-3.5)
j)2345-1000:[19-2(21-18)^2]
k)205-[1200-(4^2-2.3)^3]:40
l)500-{5[409-(2^3.3-21)^2]+10^3}:15
n)(-23)+13+(-17)+57
o)(-123)+ -13+(-7)
p)-10+45+ (- -455) + -750
h)9.40-37-2.13-52
1) Tính nhanh:
a, 125 x 3 + 125 x 125 x 6
b, ( 245 x 99 + 245 ) - ( 145 x 101 - 145 )
c, 154 x ( 28 + 52 ) - 45 x ( 26 + 54 )
a) 125.3+125.125.6
=125.3+125.750
=125.(3+750)
=125.753
=94125
b) (245.99+245)-(145.101-145)
=(245.(99+1))-(145.(101-1))
=245.100-145.100
=(245-145).100
=100.100
=10000
c) 154.(28+52)-45.(26+54)
=154.80-45.80
=(154-45).80
=109.80
=8720
a) 125x3+125+125x6
=125x(3+1+6)
=125x10
=1250
b) (245x99+245)-(145x101-145)
=(245x99+245)-(145x100)
=(245x100)-14500
=24500-14500
10000
c) 154x80-45x80
=80x(145-45)
=80x100
=8000
a, 125 x 3 + 125 x 125 x 6
=125 x 3 + 125 x 750
=125 x( 3+750)
=125 x753
=94125
b, ( 245 x 99 + 245 ) - ( 145 x 101 - 145 )
=[245 x ( 99+1 )] - [145 x ( 101-1 )]
=( 245 x 100 ) - ( 145 x 100 )
=24500 - 14500
=10 000
c, 154 x ( 28 + 52 ) - 45 x ( 26 + 54 )
=154 x 80 - 45 x 80
=(154-45)x80
=109 x80
=8720
Tìm x, biết:
a) x : 4 5 + 5 2 = − 3 3 4
b) x − 3 4 = 1 5 4
a ) x : 4 5 + 5 2 = − 3 3 4 ⇒ x : 4 5 = − 3 3 4 − 5 2 ⇒ x : 4 5 = − 11 2 ⇒ x = − 22 5 .
b ) x − 3 4 = 1 5 4 ⇒ x − 3 4 = 9 4 ⇒ x = 3 x − 3 4 = − 9 4 ⇒ x = − 3 2 .
A=3-1/10-1/40-1/88-1/154
(a+1)+(a+2)+(a+3)+(a+4)+.....+(a+10)=205
(ax10)x(1+2+3+4+...+10)=205
(ax10)+55=205
ax10=205-55=150
a=150/10=15
ax10+55=205
ax10=205-55
ax10=150
a=150:10
a=15
k cho mik nhé
x+(x+1)+(x+2)+(x+3)+...+(x+10)=154
Ta có: x + (x+1)+(x+2)+...+(x+10)=154
=> (x+x+..+x) + (1+2+...+10)=154
=> 10x + 55 = 154
=> 10x = 154 - 55
=> 10x =99
=> x = 99:10
=> x=9,9
Vậy x = 9,9
x+(x+1)+(x+2)+...+(x+10)=154
x.11+(1+2+3+4+5+6+7+8+9+10)=154
x.11+ 55 = 154
x.11 =154-55
x.11 =99
x =99 : 11
x =9
x + (x +1) + (x +2) + (x +3) +... + (x+10) = 154
(X x 10) + (1+2+3+..+10) = 154
(X x 10) + (1 + 10) x 10 : 2 = 154
X x 10 + 55 = 154
X x 10 = 154 - 55
X x 10 = 99
X = 99 : 10
x = 9.9