a: \(-145\cdot\left(13-57\right)+57\left(10-145\right)\)

\(=-145\cdot13+145\cdot57+57\cdot10-57\cdot145\)

\(=-145\cdot13+57\cdot10\)

=-1885+570

=-1315

b: \(17\left(15-16\right)+16\left(17-20\right)\)

\(=17\cdot15-17\cdot16+16\cdot17-16\cdot20\)

\(=17\cdot15-16\cdot20=255-320=-65\)

c: \(-38\left(25-4\right)+25\left(-4+38\right)\)

\(=-38\cdot25+38\cdot4-25\cdot4+25\cdot38\)

\(=38\cdot4-25\cdot4=4\cdot13=52\)

\(\left(-25\right)\cdot125\cdot4\cdot\left(-8\right)\cdot\left(-17\right)\\ =\left[\left(-25\right)\cdot4\right]\cdot\left[125\cdot\left(-8\right)\right]\cdot\left(-17\right)\\ =\left(-100\right)\cdot\left(-1000\right)\cdot\left(-17\right)\\ =...\)

Ok, thế thôi. Chúc bạn học tốt nha.

(-25).125.4.(-8).(-17)

=[(-25).4].[125.(-8)].(-17)

=(-100).(-1000).(-17)

=100000.(-17)

=-1700000

\(A=5a^3b^4-9a^{11}b^2=a^3b^2\cdot5b^2-a^3b^2\cdot9a^8=a^3b^2\left(5b^2-9a^8\right)\)

Thay \(a=-1\) và \(b=2\) vào biểu thức A, ta có:

\(A=\left(-1\right)^3\cdot2^2\left(5\cdot2^2-9\left(-1\right)^8\right)=-1\cdot4\left(5\cdot4-9\cdot1\right)=-4\left(20-9\right)=-4\cdot11=-44\)

Có vẻ như đề bài biểu thức B không đúng vậy. Sửa \(by\) ở cuối thành \(ay\).

\(B=ax+by+bx+ay=\left(ax+ay\right)+\left(bx+by\right)=a\left(x+y\right)+b\left(x+y\right)=\left(a+b\right)\left(x+y\right)\)

Thay \(a+b=-2\) và \(x+y=17\) vào biểu thức B, ta có:

\(B=-2\cdot17=-34\)

= 37 . ( 28 + 82 ) + 63 . ( 69 + 41 )

= 37 .         100    + 63 .          110

= 3700                  +          6930

= 10630

hok tốt

37.28 + 37.82 + 63.69 + 63.41

= 37.(28+82) + 63.(69+41)

= 37.110 + 63.110

= 110.(37+63)

= 110.100

= 11 000

=[\(\left(\frac{2}{3}.\frac{5}{7}+\frac{2}{3}.\frac{2}{7}\right).\left(\frac{-1}{3}\right)\)]

=[\(\left(\frac{2}{3}\right).\left(\frac{5}{7}+\frac{2}{7}\right).\left(\frac{-1}{3}\right)\)]

=[\(\left(\frac{2}{3}.1\right).\frac{-1}{3}\)]

=\(\frac{-1}{3}\)

(2/3.5/7 + 2/3: 7/2). -1/3

=(10/21 + 2/3x2/7 ) . -1/3

=(10/21 + 4/21) . -1/3

=-10/63 - 4/63

=-14/63

(2/3.5/7+2/3:7/2)-1/3

=(2/3.5/7+2/3x2/7)-1/3

=[2/3.(5/7+2/7)]-1/3

=[2/3x1]-1/3

=2/3-1/3

=1/3

HT

\(=\dfrac{11}{4}\cdot\left(-1\right)\cdot\dfrac{8}{33}=\dfrac{2}{3}\cdot\left(-1\right)=-\dfrac{2}{3}\)

\(\frac{-1}{3}:\frac{-5}{6}=\frac{-1}{3}\times\frac{-6}{5}=\frac{2}{5}\)

@muối

(-1/3) : (-5/6) = 2/5