giúp em  bài với ạ,em cảm ơn, em đang vội ạ

\(a,=-15x^3+10x^4+20x^2\\ b,=2x^3+2x^2+4x-x^2-x-2=2x^3+x^2+3x-2\)

\(a,\dfrac{-13}{5}-\dfrac{-7}{15}.\dfrac{120}{63}+\dfrac{4}{5}\\ =\dfrac{-13}{5}+\dfrac{8}{9}+\dfrac{4}{5}\\ =\dfrac{-77}{45}+\dfrac{4}{5}\\ =\dfrac{-41}{45}\\ b.\left(7\dfrac{5}{9}+2\dfrac{2}{3}\right)-5\dfrac{2}{9}\\ =\left(\dfrac{68}{9}+\dfrac{8}{3}\right)-\dfrac{47}{9}\\ =\dfrac{92}{9}-\dfrac{47}{9}\\ =5\)

2)\(-\dfrac{13}{5}--\dfrac{7}{15}.\dfrac{120}{63}+\dfrac{4}{5}\)
\(=-\dfrac{13}{5}+\dfrac{7.15.8}{15.9.7}+\dfrac{4}{5}\)
\(=-\dfrac{13}{5}+\dfrac{8}{9}+\dfrac{4}{5}\)
\(=\left(-\dfrac{13}{5}+\dfrac{4}{5}\right)+\dfrac{8}{9}\)
\(=-\dfrac{9}{5}+\dfrac{8}{9}\)
\(=\dfrac{-81+40}{45}=-\dfrac{41}{45}\)
3)\(\left(7\dfrac{5}{9}+2\dfrac{2}{3}\right)-5\dfrac{2}{9}\)
\(=\left(7\dfrac{5}{9}-5\dfrac{2}{9}\right)+2\dfrac{2}{3}\)
\(=2\dfrac{1}{3}+2\dfrac{2}{3}\)
\(=5\)

a,−135−−715.12063+45=−135+89+45=−7745+45=−4145b.(759+223)−529=(689+83)−479=929−479=5a,−135−−715.12063+45=−135+89+45=−7745+45=−4145b.(759+223)−529=(689+83)−479=929−479=5

Bài 1: 

=120(1-47-52)

=120x(-98)

=-11760

\(\left(2x+1\right)\left(y-1\right)=-7\\ \Rightarrow2x+1;y-1\in U_{\left(-7\right)}=\left\{-7;-1;1;7\right\}\)

\(=\dfrac{x^2-4y}{xy}\cdot\dfrac{x^2}{x-y}=\dfrac{x\left(x^2-4y\right)}{y\left(x-y\right)}\)

các bạn giúp đỡ mình với ạ

\(\left(x-2\right)\left(x^2-5x+1\right)-x\left(x^2+11\right)=x^3-5x^2+x-2x^2+10x-2-x^3-11x=-7x^2-2\)

\(\dfrac{45.21.25}{7.15.36}=\dfrac{3.3.3.5.7.5.5}{7.5.3.3.2.3.2}=\dfrac{25}{4}\)

45\7 x 21\15 x 25/36

=45x21x25/7x15x36

=15x3x7x3x25/7x15x3x12

=3x25/12

=75/12

=25/4

b)1024(5)-132(5)=892(5)

c)214(5).32(5)=6848(5)

d)211(5):13(5)=17(5)

2,1001(2):11(2)=91(2)

hehe làm bừa sai xin lỗivì tui ko hiểu

Bài 1:

a, 144(5) + 330(5) = 474(5)

b, 1024(5) - 132(5) = 892(5)

c)214(5) . 32(5) = 6848(5)

d)211(5) : 13(5) = 17(5)

Bài 2:

1001(2) : 11(2) = 91(2)