Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\text{a)}\left(2^{17}+17^2\right)\left(9^{15}-15^9\right)\left(4^2-2^4\right)\)
\(=\left(2^{17}+17^2\right)\left(9^{15}-15^9\right)\left[\left(2^2\right)^2-2^4\right]\)
\(=\left(2^{17}+17^2\right)\left(9^{15}-15^9\right)\left(2^4-2^4\right)\)
\(=\left(2^{17}-17^2\right)\left(9^{15}-15^9\right).0\)
\(=0\)
\(\text{b)}\left(7^{1997}-7^{1995}\right):\left(7^{1994}.7\right)=\frac{7^{1997}-7^{1995}}{7^{1994}.7}=\frac{7^{1995}\left(7^2-1\right)}{7^{1995}}=7^2-1=48\)
a) \(\frac{-5}{8}\cdot\left(\frac{4}{9}+\frac{-7}{12}\right)\)
\(=\frac{-5}{8}\cdot\frac{-5}{36}\)
\(=\frac{25}{288}\)
b) \(\left(-3,2\right)\cdot\frac{-15}{64}+\left(0,8-2\frac{4}{5}\right):3\frac{1}{2}\)
\(=\frac{3}{4}+\left(-2\right):\frac{7}{2}\)
\(=\frac{3}{4}+\frac{-4}{7}\)
\(=\frac{5}{28}\)
=))
b1: a, 612.(15+19-34)=612.0=0
b,414.(37.4+23.4-240)=414.0=0
c,(517.125-518.25)+63:23=(517.53-518.52)+33=0+27=27
b2:a,143+7.(n-17)=206
===> 7.(n-17)=206-143=63
====>n-17=63:7=9
=====>n=9+17=26
vậy n=26
b,128-28:(15-n)=124
====>28:(15-n)=128-124=4
=====> 15-n=28:4=7
=====> n=15-7=8
vậy n=8
c,3n.2+48=210
====>3n.2=210-48=162
====>3n=162:2=81=34
====>n=4
vậy n=4
\(A=-\frac{2}{3}+1\frac{1}{4}-\frac{1}{6}=-\frac{2}{3}+\frac{5}{4}-\frac{1}{6}=\frac{5}{12}\)
\(B=\frac{13}{15}\cdot0,25\cdot3+\left(\frac{8}{15}-1\frac{19}{60}\right)\div1\frac{23}{24}\)
\(B=\frac{13}{15}\cdot\frac{1}{4}\cdot3+\left(\frac{8}{15}-\frac{79}{60}\right)\div\frac{47}{24}\)
\(B=\frac{13}{20}-\frac{47}{60}\cdot\frac{24}{47}\)
\(B=\frac{13}{20}-\frac{2}{5}=\frac{1}{4}\)
a , 43 . 125 - 125 . 60
= 125 . ( 43 - 60)
= 125 . ( 64 - 60)
= 125 . 4
= 500
b , -23 + [82 - (-15-17)]
= -23 + (82 +28)
=-23 + 110
= 87
mình làm nhầm câu b