\(21.7^2-11.7^2+90.7^2+49.125.16\) 

\(=49.\left(21-11+90+125.16\right)\) 

\(=49.2100\) 

\(=102900\)

`21.7^2 -11.7^2 +90.7^2 +49.125.16`
`=7^2(21-11+90)+49.25.5.4.4`
`=7^2 .100+100.49.20`
`=49.100+100.49.20`
`=49.100(1+20)`
`=49.100.21`
`=102900`

21.7²-11.7²+90.7²+49.125.16

=21.49-11.49+90.49+49.2000

=(21-11+90+2000).49

=2100.49

=102900

21.7²-11.7²+90.7²+49.125.16

=21.49-11.49+90.49+49.2000

=(21-11+90+2000).49

=2100.49

=102900

102 900 nhé bạn

tick mình nhé

21.7²-11.7²+90.7²+49.125.16

=21.7²-11.7²+90.7²+7².2000

=(21-11+90+2000).7²

=2100.49

=102900

cau co chac ko

Giúp mik vs, pls!!!🙏🙏🏻🙏🏿

Mik hứa tick cho mn...

a,21.7^2-11.7^2+90.7^2+49.125.16

=7^2.(21-11+90)+49.(2.125.8)

=49.100+49.2000

=49.(100+2000)

=49.2100

=102900

Thanks!!!!

A,35*34+35*86+65*75+65*45

=35*[34+86]+65*[75+45]

=35*100+65*120

=35*100+65*100+65*20

=[35+65]*100+65*20

=10000+1300=11300

a)

\(\Rightarrow35.\left(34+86\right)+65.\left(75+45\right)\)

\(\Rightarrow35.120+65.120\)

\(\Rightarrow120.\left(35+65\right)=120.100=12000\)

b)

\(\Leftrightarrow21.49-11.49+90.49+49.125.16\)

\(\Rightarrow49.\left(21-11+90+2000\right)\)

\(\Rightarrow49.2100=102900\)

a) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45
= 35 . ( 34 + 86 ) + 65 . ( 75 + 45 )
= 35 . 120 + 65 . 120
= ( 35 + 65 ) . 120
= 100 . 120
= 12000

b) 21 . 7² - 11 . 7² + 90 . 7² + 49 . 125 . 16
= 21 . 49 - 11 . 49 + 90 . 49 + 49 . 125 . 16
= ( 21 - 11 + 90 ) . 49 + 49 . 125 . 8 . 2
= 100 . 49 + 49 . 2 . 1000
= 100 . 49 + 49 . 2000
= ( 100 + 2000 ) . 49
= 2100 . 49
= 102900