Question

bài 1 

b, \(\left(x-1\right)^3=-125\) 

c,\(2^{4-x}=32\)  

d, \(\frac{1}{4}.2^x+2.2^x=9.2^6\)

giúp mik với ~~~

Answer 1

           Bài làm :

b)\(\left(x-1\right)^3=-125\)

\(\Leftrightarrow\left(x-1\right)^3=\left(-5\right)^3\)

\(\Leftrightarrow x-1=-5\)

\(\Leftrightarrow x=-5+1=-4\)

c) \(2^{4-x}=32\)

\(\Leftrightarrow2^{4-x}=2^5\)

\(\Leftrightarrow4-x=5\)

\(\Leftrightarrow x=4-5=-1\)

d)\(\frac{1}{4}.2^x+2.2^x=9.2^6\)

\(\Leftrightarrow2^x.\left(\frac{1}{4}+2\right)=576\)

\(\Leftrightarrow2^x=256\)

\(\Leftrightarrow x=8\)

Answer 2

a. ( x - 1 )³ = - 125

<=> ( x - 1 )³ = - 5³

<=> x - 1 = - 5

<=> x = - 4

b. 2^{4 - x} = 32

2^{4 - x} = 2⁵

<=> 4 - x = 5

<=> x = - 1

c. \(\frac{1}{4}.2^x+2.2^x=9.2^6\)

\(\Leftrightarrow2^x\left(\frac{1}{4}+2\right)=9.64\)

\(\Leftrightarrow2^x.\frac{9}{4}=576\)

\(\Leftrightarrow2^x=256\)

<=> 2^x = 2⁸

<=> x = 8

Answer 3

\(b,\left(x-1\right)^3=-125\)

\(\left(x-1\right)^3=-\left(5\right)^3\)

\(\Rightarrow x-1=-5\)

\(\Rightarrow x=-5+1\)

\(x=-4\)

\(c,2^{4-x}=32\)

\(2^{4-x}=2^5\)

\(\Rightarrow4-x=5\)

\(\Rightarrow x=4-5\)

\(\Rightarrow x=-1\)

\(d,\frac{1}{4}.2^x+2.2^x=9.2^6\)

\(\left(\frac{1}{4}+2\right).2^x=576\)

\(\frac{9}{4}.2^x=576\)

\(2^x=576:\frac{9}{4}\)

\(2^x=256\)

\(2^x=2^8\)

\(\Rightarrow x=8\)

Học tốt

Answer 4

\(\left(x-1\right)^3=-125=>\left(x-1\right)^3=\left(-5\right)^3=>x-1=-5=>x=-5+1=>x=-4\)

vậy \(x=-4\)

\(2^{4-x}=32=>2^{4-x}=2^5=>4-x=5=>x=4-5=>x=-1\)

vậy \(x=-1\)

\(\frac{1}{4}.2^x+2.2^x=9.2^6=>\frac{1}{4}.2^x+2^x=9.64=>\frac{1}{4}.2^x+2.2^x=576\)

\(2^x.\left(\frac{1}{4}+2\right)=576=>2^x.\frac{9}{4}=576=>2^x=576:\frac{9}{4}\)

\(2^x=256=>2^x=2^8=>x=8\)

vậy \(x=8\)