tinh nhanh 294+315+575+685+706
278 + 575 + 578 + 980 + 877 + 685 = bao nhiêu?
3973 bn nhe.chuc may manva dung quen tk mk
(-315) +135 + (-315 +685)
(-315) + 135 +( - 315 + 685)
= -315 + 135 - 315 + 685
= ( 135 + 685 ) - ( 315+315)
= 820 - 630
= 190
=-280+303
=23
#Châu's ngốc
\(-315+135+\left(-315+685\right)\)
\(=-180+370\)
\(=190\)
Tính nhanh
A, 325+612+675+388
B, 268 ✖ 8+315 ✖ 33+315
C, 315 ✖ 66+315 ✖ 33+325
D, 2017 ✖ 19-2017 ✖ 8-2017
E, 3150-267-315-733-685
A) 325 + 612 + 675 + 388
= ( 325 + 612 ) + ( 675 + 388 )
= 937 + 1063
= 2000
B) 268 x 8 + 315 x 33 + 315
= ( 268 x 8 ) + ( 315 x 33 ) + 315
= 2144 + 10395 + 315
= 12539 + 315
= 12854
C) 315 x 66 + 315 x 33 + 325
= ( 315 x 66 ) + ( 315 x 33 ) + 325
= 20790 + 10395 + 325
= 31185 + 325
= 31510
D) 2017 x 19 - 2017 x 8 - 2017
= ( 2017 x 19 ) - ( 2017 x 8 ) - 2017
=38323 - 16136 -2017
= 22187 - 2017
= 20170
E) 3150 - 267 - 315 - 733 - 685
= ( 3150 - 267 ) - 315 - ( 733 - 685 )
= 2883 - 315 - 48
= 2568 - 48
= 2520
CMR: 685^3+315^3 chia hết cho 25000
\(685^3+315^3 \)
\(= (685+315).(685^2+685.315+315^2)\)
\(= 1000. (685^2+685.315+315^2)\)
Các số hạng trong ngoặc đều chia hết cho \(25 \).
\(\Rightarrow\) \(685^3+315^3\) chia hết cho \(25000.\)
CMR: 685^3+315^3 chia hết cho 25000
áp dụng hằng đẳng thức a^3+b^3=(a+b)*(a^2+b^2-a*b)
685^3+315^3=(685+315)*(685^2+315^2-685*315)=352675000 chia hết cho 25000
315+(125-X)=435
3X-15=81
575-(X-70)=445
Mk cần gấp trong hôm này ai nhanh ai dúng thì mk chọn nhez
315 + ( 125 -x ) = 435
( 125 - x ) = 435 - 315
125 - x = 120
x = 125 - 120
x = 5
a)
315 + ( 125 - x ) = 435
=> 125 - x = 435 - 315 = 120
=> x = 125 - 125 = 5
b)
3.x - 15 = 81
=> 3.x = 81 + 15 = 96
=> x = 96 : 3 = 32
c)
575 - ( x - 70 ) = 445
575 - x + 70 = 445
=> 575 + 70 - x = 445
=> 645 - x = 445
x = 645 - 445 = 200
Ủng hộ mik nhá ^_^"
315+(125-X)=435
125-X =435-315
125-X =120
X = 125-120
X =5
3X-15=81
3X = 81+15
3X = 96
X = 96 :3
X = 32
575-(X-70)=435
X-70 =575-435
X-70 =140
X =140+70
X = 210
CHỌN BÀI MÌNH NHÁ
124 - ( 118 - x ) = 217 315 + ( 146 - x ) = 401 575 - ( 6x + 70 ) = 445 315 + ( 125 - x ) = 435
\(124 - (118 - x) = 217\)
\(118-x=124-217\)
\(118-x=-93\)
\(x=118-\left(-93\right)\)
\(x=211\)
\(---\)
\(315+(146-x)=401\)
\(146-x=401-315\)
\(146-x=86\)
\(x=146-86\)
\(x=60\)
\(---\)
\(575-(6x+70)=445\)
\(6x+70=575-445\)
\(6x+70=130\)
\(6x=130-70\)
\(6x=60\)
\(x=60:6\)
\(x=10\)
\(---\)
\(315+(125-x)=435\)
\(125-x=435-315\)
\(125-x=120\)
\(x=125-120\)
\(x=5\)
#\(Toru\)
124 - ( 118 - x ) = 217
118 - x =124-217
118 - x =-93
x=118-(-93)
x= 211
315 + ( 146 - x ) = 401 \
146 - x=401-315
146 - x= 83
x= 146-83
x=63
575 - ( 6x + 70 ) = 445
6x + 70=575-445
6x + 70=130
6x=130-70
6x =60
x=60:6
x=10
315 + ( 125 - x ) = 435
125 - x=435-315
124-x=120
x=124-120
x=4
cmr 6853 + 3153 \(⋮\) 25000
Ta có :
\(685^3\equiv19125\left(mod25000\right)\)
\(315^3\equiv5875\left(mod25000\right)\)
\(\Leftrightarrow685^3+315^3\equiv25000\left(mod25000\right)\)
\(\Leftrightarrow685^3+315^3⋮25000\rightarrowđpcm\)
CMR:
a) 2015^3+2016^3 chia hết cho 2031
b) 685^3+315^3 chia hết cho 2500