anh tý năm nay 8 tuổi

a/ |x|+3/4=1/2

|x|=-1/4

=>x=1/4 hoặc -1/4

b/|x+3|-1=2

|x+3|=3

=>x+3=3 hoặc x+3=-3

x=-3 hoặc x=-6

1+1=2

quá dễ , bạn k tớ nha

tôi hông biết

Tổng là:

   10 +70+90+80+30+20=300

               Đáp số:300

k nha

Ta có :

1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100

= ( 81 + 9 ) + ( 16 + 64 ) + ( 49 + 1 ) + ( 4 + 36 ) + 1 + 100

= 90 + 80 + 50 + 40 + 1 + 100

= 361

bạn vào câu hỏi tương tự có đó giống in bài này luôn 

Theo đầu bài ta có:
\(\frac{1}{1-x}+\frac{1}{1+x}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{\left(1+x\right)+\left(1-x\right)}{\left(1-x\right)\left(1+x\right)}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{2}{1-x^2}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{2\left(1+x^2\right)+2\left(1-x^2\right)}{\left(1-x^2\right)\left(1+x^2\right)}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{\left(2+2x^2\right)+\left(2-2x^2\right)}{1-x^4}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{x^{16}}\)
\(=\frac{4}{1-x^4}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{4\left(1+x^4\right)+4\left(1-x^4\right)}{\left(1-x^4\right)\left(1+x^4\right)}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{\left(4+4x^4\right)+\left(4-4x^4\right)}{1-x^8}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{8}{1-x^8}+\frac{8}{1+x^8}+\frac{1}{1+x^{16}}\)
\(=\frac{8\left(1+x^8\right)+8\left(1-x^8\right)}{\left(1-x^8\right)\left(1+x^8\right)}+\frac{1}{1+x^{16}}\)
\(=\frac{\left(8+8x^8\right)+\left(8-8x^8\right)}{1-x^{16}}+\frac{1}{1+x^{16}}\)
\(=\frac{16}{1-x^{16}}+\frac{1}{1+x^{16}}\)
\(=\frac{16\left(1+x^{16}\right)+\left(1-x^{16}\right)}{\left(1-x^{16}\right)\left(1+x^{16}\right)}\)
\(=\frac{\left(16+16x^{16}\right)+\left(1-x^{16}\right)}{1-x^{32}}\)
\(=\frac{17+15x^{16}}{1-x^{32}}\)

15.37.4 + 120.21 + 21.5.12 = 15.4.37 + 21.2.60 + 5.12.21 = 60.37 + 42.60 + 60.21 = 60.(37 + 42 + 21) = 60.100 = 6000

97 bạn a mik viết nhầm xin lỗi nha