Câu hỏi của Lâm Nguyễn Hải

Question

a) 2x.4 = 128b) (2x + 1)3 = 125c) 2x – 26 = 6d) 64.4x = 45e) 27.3x = 243g) 49.7x = 2401h) 3x = 81k) 34.3x = 37n) 3x + 25 = 26.22 + 2.30

HT.Phong (9A5) · Accepted Answer

a) $2^x\cdot4=128$$\Rightarrow2^x\cdot2^2=2^7$$\Rightarrow2^{x+2}=2^7$$\Rightarrow x+2=7$$\Rightarrow x=5$b) $\left(2x+1\right)^3=125$$\Rightarrow\left(2x+1\right)^3=5^3$$\Rightarrow2x+1=5$$\Rightarrow2x=4$$\Rightarrow x=4:2$$\Rightarrow x=2$c) $2x-2^6=6$$\Rightarrow2x-64=6$$\Rightarrow2x=70$$\Rightarrow x=70:2$$\Rightarrow x=35$d) $64\cdot4^x=45$$\Rightarrow4^3\cdot4^x=45$$\Rightarrow4^{x+3}=45$Xem lại đềe) $27\cdot3^x=243$$\Rightarrow3^3\cdot3^x=3^5$$\Rightarrow3^{x+3}=3^5$$\Rightarrow x+3=5$$\Rightarrow x=2$g) $49\cdot7^x=2401$$\Rightarrow7^2\cdot7^x=7^4$$\Rightarrow7^{x+2}=7^4$$\Rightarrow x+2=4$$\Rightarrow x=2$h) $3^x=81$$\Rightarrow3^x=3^4$$\Rightarrow x=4$k) $3^4\cdot3^x=3^7$$\Rightarrow3^{x+4}=3^7$$\Rightarrow x+4=7$$\Rightarrow x=3$n) $3^x+25=26\cdot2^2+2\cdot3^0$$\Rightarrow3^x+25=104+2$$\Rightarrow3^x+25=106$$\Rightarrow3^x=81$$\Rightarrow3^x=3^4$$x=4$Câu trả lời: a) $2^x\cdot4=128$$\Rightarrow2^x\cdot2^2=2^7$$\Rightarrow2^{x+2}=2^7$$\Rightarrow x+2=7$$\Rightarrow x=5$b) $\left(2x+1\right)^3=125$$\Rightarrow\left(2x+1\right)^3=5^3$$\Rightarrow2x+1=5$$\Rightarrow2x=4$$\Rightarrow x=4:2$$\Rightarrow x=2$c) $2x-2^6=6$$\Rightarrow2x-64=6$$\Rightarrow2x=70$$\Rightarrow x=70:2$$\Rightarrow x=35$d) $64\cdot4^x=45$$\Rightarrow4^3\cdot4^x=45$$\Rightarrow4^{x+3}=45$Xem lại đềe) $27\cdot3^x=243$$\Rightarrow3^3\cdot3^x=3^5$$\Rightarrow3^{x+3}=3^5$$\Rightarrow x+3=5$$\Rightarrow x=2$g) $49\cdot7^x=2401$$\Rightarrow7^2\cdot7^x=7^4$$\Rightarrow7^{x+2}=7^4$$\Rightarrow x+2=4$$\Rightarrow x=2$h) $3^x=81$$\Rightarrow3^x=3^4$$\Rightarrow x=4$k) $3^4\cdot3^x=3^7$$\Rightarrow3^{x+4}=3^7$$\Rightarrow x+4=7$$\Rightarrow x=3$n) $3^x+25=26\cdot2^2+2\cdot3^0$$\Rightarrow3^x+25=104+2$$\Rightarrow3^x+25=106$$\Rightarrow3^x=81$$\Rightarrow3^x=3^4$$x=4$

『Kuroba ム Tsuki Ryoo ︵²ᵏ⁷』 · Answer

`@` `\text {Ans}``\downarrow``a)``2^x*4 = 128``=> 2^x = 128 \div 4``=> 2^x = 2^7 \div 2^2``=> 2^x = 2^5``=> x = 5`Vậy, `x = 5.``b)`$\left(2x+1\right)^3=125$`=> (2x + 1)^3 = 5^3``=> 2x + 1 = 5``=> 2x = 5-1``=> 2x = 4``=> x = 4 \div 2``=> x = 2`Vậy, `x = 2``c)`$2x-2^6=6$`=> 2x = 6+2^6``=> 2x = 70``=> x = 70 \div 2``=> x = 35`Vậy, `x = 35``d)`$64\cdot4^x=45$ Bạn xem lại đề`e)``27*3^x = 243``=> 3^3 * 3^x = 3^5``=> 3^(3 + x) = 3^5``=> 3 + x = 5``=> x = 5 - 3``=> x = 2`Vậy, `x = 2``g)``49* 7^x = 2401``=> 7^2 * 7^x = 7^4``=> 7^(2 + x) = 7^4``=> 2 + x = 4``=> x = 4 - 2``=> x = 2`Vậy, `x = 2``h)``3^x = 81``=> 3^x = 3^4``=> x = 4`Vậy, `x = 4``k)``3^4 * 3^x = 3^7``=> 3^(4 + x) = 3^7``=> 4 + x = 7``=> x = 7 - 4``=> x = 3`Vậy, `x = 3``n)``3^x + 25 = 26*2^2 + 2*3^0``=> 3^x + 25 = 104 + 2``=> 3^x + 25 = 106``=> 3^x = 106 - 25``=> 3^x = 81``=> 3^x = 3^4``=> x = 4`Vậy, `x = 4.`$#48Cd$Câu trả lời: `@` `\text {Ans}``\downarrow``a)``2^x*4 = 128``=> 2^x = 128 \div 4``=> 2^x = 2^7 \div 2^2``=> 2^x = 2^5``=> x = 5`Vậy, `x = 5.``b)`$\left(2x+1\right)^3=125$`=> (2x + 1)^3 = 5^3``=> 2x + 1 = 5``=> 2x = 5-1``=> 2x = 4``=> x = 4 \div 2``=> x = 2`Vậy, `x = 2``c)`$2x-2^6=6$`=> 2x = 6+2^6``=> 2x = 70``=> x = 70 \div 2``=> x = 35`Vậy, `x = 35``d)`$64\cdot4^x=45$ Bạn xem lại đề`e)``27*3^x = 243``=> 3^3 * 3^x = 3^5``=> 3^(3 + x) = 3^5``=> 3 + x = 5``=> x = 5 - 3``=> x = 2`Vậy, `x = 2``g)``49* 7^x = 2401``=> 7^2 * 7^x = 7^4``=> 7^(2 + x) = 7^4``=> 2 + x = 4``=> x = 4 - 2``=> x = 2`Vậy, `x = 2``h)``3^x = 81``=> 3^x = 3^4``=> x = 4`Vậy, `x = 4``k)``3^4 * 3^x = 3^7``=> 3^(4 + x) = 3^7``=> 4 + x = 7``=> x = 7 - 4``=> x = 3`Vậy, `x = 3``n)``3^x + 25 = 26*2^2 + 2*3^0``=> 3^x + 25 = 104 + 2``=> 3^x + 25 = 106``=> 3^x = 106 - 25``=> 3^x = 81``=> 3^x = 3^4``=> x = 4`Vậy, `x = 4.`$#48Cd$

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