giup mik di

\(5871:\left[928-\left(247-82.5\right)\right]\)

\(=5871:\left[928-\left(247-460\right)\right]\)

\(=5871:\left[928-\left(-213\right)\right]\)

\(=5871:1141\)

\(4^x=4^3.4^5\Rightarrow x=3+5=8\)

\(2^x=8.128\Rightarrow2^x=2^3.2^7\Rightarrow x=3+7=10\)

\(4^X=4^3.4^5\)

\(4^X\)=\(4^7\)

\(\Rightarrow\)X=7

\(2^X=8.128\)

\(2^X=2^3.2^7\)

\(2^X\)=\(2^{10}\)

\(\Rightarrow\)x=10

chú ý: dấu nhân kí hiệu là .

4^x=4³.4⁵

4^x=4³⁺⁵

4^x=4⁸

<=> x=8

2^x=8.128

2^x=2³.2⁷

2^x=2³⁺⁷

2^x=2¹⁰

<=> x=10

\(10+2\times x=4^5:4\)

\(10+2\times x=256\)

           \(2\times x=256-10\)

           \(2\times x=246\)

                   \(x=246:2\)

                   \(x=123\)

256x57+256xX=25600

x=25600/256

x=100

x=100-57

x=43

x=......................

Đáp án là C

a ) x + 2 1 3 = 2 5 6 ⇒ x = 2 5 6 − 2 1 3 = 1 2 .

b ) x + 8 2 3 = 3 1 3 ⇒ x = 3 1 3 − 8 2 3 = 10 3 − 26 3 = − 16 3 .

`@` `\text {Ans}`

`\downarrow`

`a,`

`x \times 274 - 256 \times x = 5130`

`x \times (274 - 256) = 5130`

`x \times 18 = 5130`

`x = 5130 \div 18`

`x = 285`

Vậy, `x = 285`

`b,`

`x \times 18 \times 19 = 43434`

`x \times 342 = 43434`

`x = 43434 \div 342`

`x = 127`

Vậy, `x = 127.`