38.78-(214-1).(214+1)
cho |a|<1;|a-c|<214;|b-1|<214 cm:|ab-c|<428
Cho |a| < 1, |a - c| < 214, |b - 1| <214. Chứng minh |ab - c| < 428
Cho |a|<1;|a-c|<214;|b-1|<214. Chứng minh rằng:|ab-c|<428
Tính nhanh:
214 x 6 + 3 x 214 + 214 x 2 - 214
Giúp mik với.
214*6+3*214+214*2-214
=214*(6+3+2-1)
=214*10
=2140
~HT~ (Kick cho mik nha!!!)
214 x 6 + 3 x 214 + 214 x 2 - 214
214 x ( 6 + 3 + 2 - 1 )
214 x 10
2140
214 x(6 + 3) +428-214
214 x 9 + 214
1928 + 214
2142
214 x 35 + 214 x 63 + 214 x 2.
( 214 x 3 ) + ( 35 + 63 + 2 ) = 642 + 100
= 742
Tính bằng cách thuận tiện nhất :
745 x 214 + 254 x 214 + 214
\(745\times214+254\times214+214\)
\(=214\times745+214\times254+214\times1\)
\(=214\times\left(745+254+1\right)\)
\(=214\times1000\)
\(=214000\)
= 745 x 214 + 254 x 214 + 214 x1
= 214 x ( 745 + 254 + 1)
= 214 x 1000
= 214000
745 x 214 + 254 x 214 + 214 x 1
214 x (745 + 254 + 1 )
214 x 1000
214000
(-37).214+214.(-63)
(-37).214 + 214.(-63)
= 214. [(-37) + (-63)]
= 214. (-100)
= -21400
(-37).214 + 214.(-63)
= 214.(-37 - 63)
= 214.(-100)
= -21400
214+¨[120-(214+120)]
214+[120-(214+120)]
=214+[120-214-120]
=214+120-214-120
=(214-214)+(120-120)
=0+0
=0
214+¨[120-(214+120)]
=214+120-(214+120)
=214+120-214-120
=(214-214)+(120-120)
=0+0
=0
mk nhanh nhất lun
Tính:
a) (-173) [214+(-25)]+214(173+25)+(-25)(-13)
b)1-3-5+7+9-11-13+15+...+2009-2011-2013+2015
Ai nhanh mình tick nhé!
b)(1-3-5+7)+(9-11-13+15)+...+(2009-2011-2013+2015)
=0+0+...+0
=0
( X+1)+ ( x+2)+.......+ ( X+214)= 23632
\(\left(x+1\right)+\left(x+2\right)+...+\left(x+214\right)=23632\)
\(\Rightarrow\left(x+x+.....+x\right)+\left(1+2+....+214\right)=23632\)
\(\Rightarrow214x+23005=23632\)
\(\Rightarrow214x=627\)
\(\Rightarrow x=\frac{627}{214}\)