B

ko ghi lại đề bài

(2²+ 2¹+ 2²+2³).0.2.8.4

=0

21.7²-7².11+90.7²+49.125.16

=7².(49+21).90+125.16

=14.70+90+125.16

=(14+16).90-20+125

=20-20.125+90

=0

b)

(2²+2¹+2²+2³).2⁰.2¹.2³.2²

=(2²-2²-2²).(2³-2³).(2¹-2¹) 2⁰

=0.0.0.0

=0 

hok tốt

hariki thuận tiện mà

   21*7^2 -11*7^2 +90*7^2 +49*125*16

=7^2* ( 21 -11+ 90 ) + 7^2* 2000

=7^2* 100 + 7^2* 2000

=7^2* ( 100+ 2000 )

=49*2100

=102900

đáp số là 41650

\(a,\dfrac{5^{16}\cdot27^7}{125^5\cdot9^{11}}=\dfrac{5^{16}\cdot\left(3^3\right)^7}{\left(5^3\right)^5\cdot\left(3^2\right)^{11}}\)

\(=\dfrac{5^{16}\cdot3^{21}}{5^{15}\cdot3^{22}}=\dfrac{5}{3}\)

\(b,\left(-0,2\right)^2\cdot5-\dfrac{2^{13}\cdot27^3}{4^6\cdot9^5}\)

\(=0,04\cdot5-\dfrac{2^{13}\cdot\left(3^3\right)^3}{\left(2^2\right)^6\cdot\left(3^2\right)^5}\)

\(=0,2-\dfrac{2^{13}\cdot3^9}{2^{12}\cdot3^{10}}\)

\(=0,2-\dfrac{2}{3}\)

\(=-\dfrac{7}{15}\)

\(c,\dfrac{5^6+2^2\cdot25^3+2^3\cdot125^2}{26\cdot5^6}\)

\(=\dfrac{5^6+2^2\cdot\left(5^2\right)^3+2^3\cdot\left(5^3\right)^2}{5^6\cdot26}\)

\(=\dfrac{5^6+4\cdot5^6+8\cdot5^6}{5^6\cdot26}\)

\(=\dfrac{5^6\left(1+4+8\right)}{5^6\cdot26}\)

\(=\dfrac{13}{26}\)

\(=\dfrac{1}{2}\)

#\(Toru\)

\(a,\dfrac{5^{16}.27^7}{125^5.9^{11}}=\dfrac{\left(5^2\right)^8.9^7.3^7}{25^5.5^5.9^{11}}\\ =\dfrac{25^8.9^7.\left(3^2\right)^3.3}{25^5.\left(5^2\right)^2.5.9^{11}}=\dfrac{25^8.9^7.9^3.3}{25^5.25^2.5.9^{11}}\\ =\dfrac{25^8.9^{10}.3}{25^7.5.9^{11}}=\dfrac{25^7.9^{10}.25.3}{25^7.9^{10}.5.9}\\ =\dfrac{25.3}{5.9}=\dfrac{5.5.3}{5.3.3}=\dfrac{5}{3}\)

ai tra loi dung cho h

ko biêt

a, -326-(115-326)=-326-(-326)-115=(-326+326)-115=-115

b,-13-18-(-42)-15=-13-18+42-15=-4

c,(-558+558)+(-50+50)=0+0=0

d,35-12+16=39

e,18.17-3.6.7=18.17-18.7=18.(17-7)=18.10=180

f,21.7²-11.7²+90.7²+49.125.10

=21.7²-11.7²+90.7²+7².1250

=7².(21-11+90+1250)

=7².1350=49.1350

=66150

Bài 1: Thực hiện phép tính ( tính nhanh nếu có thể )

      A = 21 . 7² - 11 . 7² + 90 . 7² + 49 .125 .16

=>  A=21.7²-11.7²+90.7²+7².125.16

=>   A=7².(21-11+90+125.16)

=>    A=7².2100=102900

cảm ơn nguyen tung lam .nhưng mình cần cậu giúp cả 2 ý . nen cau giup minh not y b nhe

Bài 1: Thực hiện phép tính ( tính nhanh nếu có thể )

      A = 21 . 7² - 11 . 7² + 90 . 7² + 49 .125 .16

      B = 2 + 2 + 2 + 2 ...+  2

           mink không biết nữa

a, \(35\times34+35\times86+65\times75+65\times45\)

\(=35\times(34+86)+65\times(75+45)\)

\(=35\times120+65\times120\)

\(=(35+65)\times120=100\times120=12000\)

b, \(21\times7^2-11\times7^2+90\times7^2+49\times125\times16\)

Làm nốt

a)35 x 34 + 35x 86 + 65 x 75 + 65 x 45

=35 x (34+86) + 65 x (75 + 45)

=35 x 120 + 65 x 120

=120 x (35 + 65)

=120 x 100

=12000

Chúc học tốt!

b) 21 x 7² - 11 x  7² + 90 x 7² + 49 x  125 x 16

=7² x (21-11+90) + 49  x  2000

=49 x 100 + 49 x 20 x 100

=49 x 100 x (1+20)

=4900 x 21

=102900

Chúc học tốt!

\( 21 . 7^2 - 11 . 7^2 + 90 . 7^2 + 49 . 125 . 16\)

\(=21.7^2-11.7^2+90.7^2+7^2(125.8).2\)

\(=7^2(21-11+90+2000)\)

\(=49.2100=102900\)

a) \(=\left(\left(-\frac{1}{4}-\frac{5}{3}\right)+\frac{7}{33}\right)-\left(-\frac{15}{12}+\frac{6}{11}-\frac{48}{49}\right)\)

\(=\left(-\frac{23}{12}+\frac{7}{33}\right)+\frac{15}{12}-\frac{6}{11}+\frac{48}{49}\)

\(=\left(-\frac{23}{12}+\frac{15}{12}\right)+\left(\frac{9}{33}-\frac{6}{11}\right)+\frac{48}{49}\)

\(=-\frac{2}{3}-\frac{3}{11}+\frac{48}{49}\)

\(=\frac{65}{1617}\)

b) \(=\frac{11}{125}+\left(-\frac{17}{18}+\frac{4}{9}\right)+\left(-\frac{5}{7}+\frac{17}{14}\right)\)

\(=\frac{11}{125}-\frac{1}{2}+\frac{1}{2}\)

\(=\frac{11}{125}\)

tính từng cái là đc

cau a em