Bài 1:

b: \(\frac{\frac37-\frac{3}{13}+\frac{3}{17}}{\frac57-\frac{5}{13}+\frac{5}{17}}\)

\(=\frac{3\left(\frac17-\frac{1}{13}+\frac{1}{17}\right)}{5\left(\frac17-\frac{1}{13}+\frac{1}{17}\right)}=\frac35\)

c: \(\frac{5^4\cdot4^4\cdot5^4}{5^{10}\cdot4^5}=\frac{5^8\cdot4^4}{5^{10}\cdot4^5}=\frac{1}{5^2\cdot4}=\frac{1}{100}\)

d: \(\left|x-2007\right|+\left|2y-2020\right|^{2021}=0\)

=>x-2007=0 và 2y-2020=0

=>x=2007 và 2y=2020

=>x=2007 và y=1010

Bài 2:

b: \(A=\frac{1}{2^2}+\frac{1}{2^4}+\cdots+\frac{1}{2^{100}}\)

=>\(4A=1+\frac{1}{2^2}+\cdots+\frac{1}{2^{98}}\)

=>4A-A=\(1+\frac{1}{2^2}+\cdots+\frac{1}{2^{98}}-\frac{1}{2^2}-\frac{1}{2^4}-\cdots-\frac{1}{2^{100}}\)

=>3A=\(1-\frac{1}{2^{100}}\)

=>3A<1

=>A<1/3

c: \(H=\left|x-3\right|+\left|4+x\right|\)

\(=\left|x+4\right|+\left|3-x\right|\ge\left|x+4+3-x\right|=7\forall x\)

Dấu '=' xảy ra khi (x-3)(x+4)<=0

=>-4<=x<=3

Nhìn nó rối ghê á

1: =-15+10-35+28=-32

3: \(=20-12-8+12=20-8=12\)

5: \(=-18-42-21-35=-116\)

3: \(=-15+18-12+8=-27+26=-1\)

2: \(=-12+21-15+10=9-5=4\)

mấy câu này mình trả lời xong rùi câu dưới

1: =-15+10-35+28=-12

3: =20-12-8+12=12

2) -3(4 - 7) + 5(-3 + 2)

= -3.4 + 3.7 - 5.3 + 5.2

= -12 + 21 -15 + 10

= 31 - 27

= 4

4) -5(2 - 7) + 4(2 - 5)

= -5.2 + 5.7 + 4.2 - 4.5

= -10 + 35 + 8 - 20

= 38 - 30

= 8

5: \(=3-\dfrac{1}{4}+\dfrac{2}{3}-5+\dfrac{1}{3}+\dfrac{6}{5}-6+\dfrac{7}{4}-\dfrac{3}{2}\)

\(=3-5-6+\dfrac{-1}{4}+\dfrac{7}{4}+\dfrac{2}{3}+\dfrac{1}{3}+\dfrac{6}{5}-\dfrac{3}{2}\)

\(=-8+\dfrac{3}{2}+1+\dfrac{-3}{10}\)

\(=-7+\dfrac{15-3}{10}=-7+\dfrac{6}{5}=-\dfrac{29}{5}\)

6: \(=6-\dfrac{2}{3}+\dfrac{1}{2}-5-\dfrac{5}{3}+\dfrac{3}{2}-3+\dfrac{7}{3}-\dfrac{5}{2}\)

\(=6-5-3-\dfrac{2}{3}-\dfrac{5}{3}+\dfrac{7}{3}+\dfrac{1}{2}+\dfrac{3}{2}-\dfrac{5}{2}\)

\(=-2-\dfrac{1}{2}=-\dfrac{5}{2}\)

7: \(=\dfrac{5}{3}-\dfrac{3}{7}+9-2-\dfrac{5}{7}+\dfrac{2}{3}+\dfrac{8}{7}-\dfrac{4}{3}-10\)

\(=9-2-10+\dfrac{5}{3}+\dfrac{2}{3}-\dfrac{4}{3}+\dfrac{-3}{7}-\dfrac{5}{7}+\dfrac{8}{7}\)

=-3+1

=-2

8: \(=8-\dfrac{9}{4}+\dfrac{2}{7}+6+\dfrac{3}{7}-\dfrac{5}{4}-3-\dfrac{2}{4}+\dfrac{9}{7}\)

\(=8+6-3+\dfrac{2}{7}+\dfrac{3}{7}+\dfrac{9}{7}-1-\dfrac{2}{4}\)

\(=11+2-1-\dfrac{1}{2}\)

=11+1/2

=11,5

DDễ

10: =-10+14+20-12

=4+8

=12

8: =21-35-18+63

=3+28

=31

7)=-5.(-1)-7.2

=5-14

=-9

8)=7.(-2) - 9.(-5)

= -14-(-45)

=31

9)= -8.(-1)+7.4

=8+28

=36

10)= -2.(-2)+4.2

=4+8

=12