=1297x100=129700

=129700

\(99\times36+57\times99+99-84\times99\)

\(=99\times(36+57+1-84)\)

\(=99\times10=990\)

99 x 36 + 57 x 99 - 84 x 99

= 99 x ( 36 + 57 + 1 - 84 )

= 99 x 10

= 990

99 x 36 + 57 x 99 + 99 - 84 x 99

= 99 x ( 36 + 57 + 99 - 84 )

= 99 x 108

= 10.692

701 x 153 - 153 x 200 - 153 x 4 

= ( 701 - 200 - 4 ) x 153

= 497 x 153

= 76041

701 x 153 - 153 x 200  - 153 x 4

= 153 x ( 701 - 200 - 4 )

= 153 x 497

= 76041

701 x 153 - 153 x 200 - 153 x 4

= 153 x ( 701 - 200 - 4 )

= 153 x 497

= 76041

B1:

\(a.301^2=\left(300+1\right)^2=300^2+2.300.1+1^2\\ =90000+600+1=90601\\ b.88^2+2.88.12+12^2=\left(88+12\right)^2=100^2=10000\\ c.99.100=100^2-100=10000-100=9900\\ d,153^2+94.153+47^2=153^2+2.153.47+47^2=\left(153+47\right)^2=200^2=40000\)

B2:

\(A=x^2-20x+101\\ =x^2-2.x.10+10^2+1\\ =\left(x-10\right)^2+1\ge1\forall x\in R\left(Vì:\left(x-10\right)^2\ge0\forall x\in R\right)\\ \Rightarrow min_A=1\Leftrightarrow x-10=0\Leftrightarrow x=10\)

3640

3640

3640

99 x 15 + 15 = 15 x ( 99 + 1) = 15 x 100 = 1500

7,48 x ( 99 + 1 )

= 7,48 x 100

= 748

7,48 x ( 99 + 1 )

= 7,48 x 100

= 748

748

S =[1+(-2)] +[3+(-4)] +...+[97+(-98)] +99

= (-1) + (-1) +.....+(-1) + 99  có  98:2 =49 số (-1)

=(-1).49 + 99 = 99 -49 = 50

S =50

S=1+(-2)+3+(-4)+...+(-98)+99

S=(-1)+(-1)+(-1)+...+(-1)

S=(-1).49,5  (49,5 con so 1 )

S=-49,5

Vay S=-49,5

**** nhe

=(11+99)+(22+88)+(33+77)+(44+66)+55

=100+100+100+100+55

=400+55

=455

=(11+99)+(22+88)+(33+77)+(44+66)+55

=100+100+100+100+55

=400+55

=455

Hình như các bn làm sai rồi

[11 + 99] + [22 + 88] + [33 + 77] + [44 + 66]

= 110 + 110 + 110 + 110 

=110 x 4

=440

mình nghĩ là như z