128.912 = 1816

Ta có: 128.912 = (4.3)8.912 =48.38.912 =(22)8.(32)4.912

= 216.94.912 = 216.916= (2.9)16 = 1816

Vế trái bằng vế phải nên đẳng thức được chứng minh

Tính nhanh

1001 * 789 + 456 * 128 + 912 * 436 

1001 . 789 + 456 . 128 + 912 .436 = 1245789

k nha

Tìm y biết

16/3+0,357×(y-5/3)=3/4:9/4+5

bạn hỏi để câu L-I-K-E ak

\(11\div\left\{\frac{7}{8}-3\cdot\left[0,25\div\left(1\frac{1}{3}+2\cdot\frac{1}{3}\right)\right]\right\}\)

\(=11\div\left\{\frac{7}{8}-3\cdot\left[\frac{1}{4}\div\left(\frac{4}{3}+2\cdot\frac{1}{3}\right)\right]\right\}\)

\(=11\div\left\{\frac{7}{8}-3\cdot\left[\frac{1}{4}\div\left(\frac{4}{3}+\frac{2}{3}\right)\right]\right\}\)

\(=11\div\left\{\frac{7}{8}-3\cdot\left[\frac{1}{4}\div2\right]\right\}\)

\(=11\div\left\{\frac{7}{8}-3\cdot\frac{1}{8}\right\}\)

\(=11\div\left\{\frac{7}{8}-\frac{3}{8}\right\}\)

\(=11\div\frac{1}{2}\)

\(=22\)

b) 101*789 + 456*128 - 789 + 912*436

= 789*100 + 456*128 + 912*436

= 789*100 + 912*64 + 912*436

= 789*100 + 912*500

= 100*(789 + 912*5)

= 100*5349

= 534900

\(a)\)\(11\div\left\{\frac{7}{8}-3\times\left[0,25\div\left(1\frac{1}{3}+2\times\frac{1}{3}\right)\right]\right\}\)

\(=\)\(11\div\left\{\frac{7}{8}-3\times\left[\frac{1}{4}\div\left(\frac{4}{3}+\frac{2}{3}\right)\right]\right\}\)

\(=\)\(11\div\left\{\frac{7}{8}-3\times\left[\frac{1}{4}\div2\right]\right\}\)

\(=\)\(11\div\left\{\frac{7}{8}-3\times\left[\frac{1}{4}\times\frac{1}{2}\right]\right\}\)

\(=\)\(11\div\left\{\frac{7}{8}-3\times\frac{1}{8}\right\}\)

\(=\)\(11\div\left\{\frac{7}{8}-\frac{3}{8}\right\}\)

\(=\)\(11\div\frac{1}{2}\)

\(=\)\(22\)

\(b)\)\(101\times789+456\times128-789+912\times436\)

\(=\)\(79689+58368-789+397632\)

\(=\)\(534900\)

Lời giải;
$9^9+9^{10}+9^{11}+9^{12}=9^9(1+9+9^2+9^3)$
$=9^9.820$ không chia hết cho 100 bạn nhé. Bạn xem lại đề.

a)12⁸.9¹²=(2².3)⁸.(3²)¹²=2¹⁶.3⁸.3²⁴=2¹⁶.3³²=2¹⁶.(3²)¹⁶=2¹⁶.9¹⁶=(2.9)¹⁶=18¹⁶

=>12⁸.9¹²=18¹⁶

b)75²⁰=(3.5²)²⁰=3²⁰.5⁴⁰=(3²)¹⁰.5¹⁰.5³⁰=9¹⁰.5¹⁰.5³⁰=(9.5)¹⁰.5³⁰=45¹⁰.5³⁰

=>75²⁰=45¹⁰.5³⁰

sorry tôi đang cần ****

Ta có:

1 1.2 + 1 3.4 + 1 5.6 + ... + 1 49.50

= 1 − 1 2 + 1 3 − 1 4 + 1 5 − 1 6 + ⋯ ⋯ + 1 49 − 1 50 = 1 + 1 3 + 1 5 + ⋯ ⋯ + 1 49 − 1 2 + 1 4 + 1 6 + ⋯ ⋯ + 1 50 = 1 + 1 2 + 1 3 + 1 4 + 1 5 + ⋯ ⋯ + 1 50 − 2. 1 2 + 1 4 + 1 6 + ⋯ ⋯ + 1 50 = 1 + 1 2 + 1 3 + 1 4 + 1 5 + ⋯ ⋯ + 1 50 − 1 + 1 2 + 1 3 + ⋯ ⋯ + 1 25 = 1 26 + 1 27 + 1 28 + ... + 1 50       ( d p c m )

\(n^6-n^4-n^2+1\\ =n^4\left(n^2-1\right)-\left(n^2-1\right)\\ =\left(n^4-1\right)\left(n-1\right)\left(n+1\right)\\ =\left(n^2-1\right)\left(n^2+1\right)\left(n-1\right)\left(n+1\right)\\ =\left(n-1\right)\left(n+1\right)\left(n-1\right)\left(n+1\right)\\ =\left(n-1\right)^2\left(n+1\right)^2\)

Đáp án là D