=> (x - 1)² = 64 => (x - 1)² = 8² => x - 1 = 8 => x = 9

b/ => x² - x = 0 

=> x(x - 1) = 0 

=> x = 0 hoặc x - 1 = 0 => x = 1

a) 2 . (x - 1)² = 128

(x - 1)² = 64 = + 8

=> x = 9 hoặc x = -7

b) x² = x

<=> x \(\in\) {0; -1; 1}

cho hỏi cau a sao ko co x

Co x dau ma tim

\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)

\(2\times A=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)

\(2\times A-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\right)\)

\(A=1-\frac{1}{128}\)

\(A=\frac{127}{128}\)

\(B=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)

\(2\times B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)

\(B=1-\frac{1}{16}=\frac{15}{16}\)

\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)

\(\Leftrightarrow4\times x+\frac{15}{16}=1\)

\(\Leftrightarrow4\times x=\frac{1}{16}\)

\(\Leftrightarrow x=\frac{1}{64}\)

2^x+6=128

=> 2^x+6=2⁷

=> x+6=7

=> x=7-6

=> x=1

2^x . 4 = 128

=> 2^x = 32

=> 2^x = 2⁵

=> x = 5

a) x-7 = - 5

<=> x= 2

b) 128 - 3.x.(x+4) = 23

<=> - 3x² - 12x +105=0

<=> -x² -4x + 35 =0

\(\Delta'=156\Rightarrow\sqrt{\Delta'}=2\sqrt{39}\)

=> \(\left[{}\begin{matrix}x=-2+\sqrt{39}\\x=-2-\sqrt{39}\end{matrix}\right.\)

vậy S= \(\left\{-2+\sqrt{39};-2-\sqrt{39}\right\}\)

\(\left(\frac{3}{20}+\frac{1}{20}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\Leftrightarrow\frac{4}{20}-x=\frac{21}{128}.\frac{32}{9}\)

\(\Leftrightarrow\frac{1}{5}-x=\frac{7}{12}\)

\(\Leftrightarrow x=\frac{1}{5}-\frac{7}{12}\)

\(\Leftrightarrow x=-\frac{23}{60}\)

Vậy \(x=\frac{-23}{60}\)

Bài làm

\(\left(\frac{3}{20}+\frac{1}{20}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\left(\frac{3}{20}+\frac{1}{20}-x\right)=\frac{21}{128}.\frac{32}{9}\)

\(\frac{4}{20}-x=\frac{7}{4}.\frac{1}{3}\)

\(\frac{4}{20}-x=\frac{7}{12}\)

\(x=\frac{4}{20}-\frac{7}{12}\)

\(x=\frac{12}{60}-\frac{35}{60}\)

\(x=-\frac{23}{60}\)

Vậy \(x=-\frac{23}{60}\)

\(x=-\frac{37}{15}\)

ko biết mk mới học lớp 5 nữa

 Khó quá thì nên hoc24 .vn 

Nếu đúng thì ấnĐúng 2 không những thees sau khi ấn sẽ may mắn cả năm

a) 2^x . 4 = 128

2^x = 128 : 4

2^x = 32

2^x = 2⁵  (vì 32 = 2⁵)

x = 5

b) x¹⁵ = x

x¹⁵ - x = 0

x.(x¹⁴ -1) =0

x = 0 hoặc x¹⁴ = 1

x = 0 hoặc x = 1 hoặc x = -1

c) [2x + 1]³ = 5³ (vì 125 = 5³)

2x + 1 = 5

x = (5 - 1)/2

x = 2

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