a: 3x^2y(3x-4y)

=3x^2y*3x-3x^2y*4y

=9x^3y-12x^2y^2

c: (3x+5)(3xy-5x)

=9x^2y-15x^2+15xy-25x

a) \(19.43+\left(-20\right).43-\left(-40\right)\)

\(=43.\left(19-20\right)+40\)

\(=-43+40\)

\(=-3\)

b) \(6^7:6^5+3.3^2-2021^0\)

\(=6^2+3^3-1\)

\(=36+27-1\)

\(=62\)

c) \(465+\left[\left(-38\right)+\left(-465\right)\right]-\left[12-\left(-42\right)\right]\)

\(=465-38+\left(-465\right)-12-42\)

\(=-92\)

a,13

b,16276

c,20

d,20

a) (-17)+5+8+17

=(-17+17)+(5+8)

=0+13

=13

b) (-4)+(-440)6(-6)+440

đề thiếu

c) 465+[58+(-465)+(-38)]

=465+58+(-465)+(-38)

=(-465+465)+(-38+58)

=0+20

=20

d) 465+[58+(-465)+(-38)]

giống bài c

465 + [(-38) + (-465)] - [12 - (-42)]
= 465 + (-503) - 54
= -92

465 + [(-38) + (-465)] - [12 - (-42)]
= 465 + (-503) - 54
= -92

465 + [(-38) + (-465)] - [12 - (-42)]

= 465 + ( - 38) + ( -465) – 12 – 42      

= [ 465 + (- 465) ] – ( 12 + 42 )       

= 0 – 54 = 0 + ( -54 ) = -54                

ai giup mik mik cho 3 hua

\(13\cdot75+25\cdot13-120\)

\(=975+325-120\)

\(=1300-120\)

\(=1180\)

\(190\cdot64+190\cdot36\)

\(=190\left(64+36\right)\)

\(=190\cdot100\)

\(=19000\)

a,13.(75+25)+120=13.100+120=1300+120=1420

b, 190.(64+36)=190.100=19000

c,465+58-465-38=58-38=20

tích nha