a: =>2^4x<2^28

=>4x<28

=>x<7

b: =>5^3x+3<5

=>3x+3<1

=>3x<-2

=>x<-2/3

a) \(16^x< 128^4\)

= (24)^x < (27)⁴

= 2^4x < 2²⁸

= 4x < 28

= x < 7 

Vậy \(x=\left\{0;1;2;3;4;5;6;\right\}\)

\(#Tuyết\)

Tích mình đi rồi mình nói thề bạn

a, \(16x^2-9\left(x+1\right)^2=0\)

\(\Leftrightarrow\left(4x\right)^2-\left(3x+3\right)^2=0\Leftrightarrow\left(4x-3x-3\right)\left(4x+2x+3\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(6x+3\right)=0\Leftrightarrow x=-\frac{1}{2};x=3\)

b, \(\left(5x-4\right)^2-49x^2=0\Leftrightarrow\left(5x-4-7x\right)\left(5x-4+7x\right)=0\)

\(\Leftrightarrow\left(-2x-4\right)\left(12x-4\right)=0\Leftrightarrow x=-2;x=\frac{1}{3}\)

c, \(5x^3-20x=0\Leftrightarrow5x\left(x^2-4\right)=0\)

\(\Leftrightarrow5x\left(x-2\right)\left(x+2\right)=0\Leftrightarrow x=0;x=\pm2\)

1: Ta có: \(16x^2-9\left(x+1\right)^2=0\)

\(\Leftrightarrow\left(4x-3x-3\right)\left(4x+3x+3\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(7x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{7}{3}\end{matrix}\right.\)

2: Ta có: \(\left(5x-4\right)^2-49x^2=0\)

\(\Leftrightarrow\left(5x-4-7x\right)\left(5x-4+7x\right)=0\)

\(\Leftrightarrow\left(2x+4\right)\left(12x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=\dfrac{1}{3}\end{matrix}\right.\)

3: Ta có: \(5x^3-20x=0\)

\(\Leftrightarrow5x\left(x-2\right)\left(x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)

a) 3x⁴ - 13x³ + 16x² - 13x + 3 = 0

(x - 3)(3x - 1)(x² - x + 1) = 0

nhưng vì x² - x + 1 # 0 nên:

x - 3 = 0 hoặc 3x - 1 = 0

x = 0 + 3         3x = 0 + 1

x = 3               3x = 1

                        x = 1/3

b) 6x⁴ + 5x³ - 38x² + 5x + 6 = 0

(x - 2)(x + 3)(3x + 1)(2x - 1) = 0

x - 2 = 0 hoặc x + 3 = 0 hoặc 3x + 1 = 0 hoặc 2x - 1 = 0

x = 0 + 2         x = 0 - 3           3x = 0 - 1          2x = 0 + 1

x = 2               x = -3               3x = -1              2x = 1

                                                x = -1/3             x = 1/2

a, 4x² - 49 = 0

⇔⇔ (2x)² - 7² = 0

⇔⇔ (2x - 7)(2x + 7) = 0

⇔{2x−7=02x+7=0⇔⎧⎪ ⎪⎨⎪ ⎪⎩x=72x=−72⇔{2x−7=02x+7=0⇔{x=72x=−72

b, x² + 36 = 12x

⇔⇔ x² + 36 - 12x = 0

⇔⇔ x² - 2.x.6 + 6² = 0

⇔⇔ (x - 6)² = 0

⇔⇔ x = 6

e, (x - 2)² - 16 = 0

⇔⇔ (x - 2)² - 4² = 0

⇔⇔ (x - 2 - 4)(x - 2 + 4) = 0

⇔⇔ (x - 6)(x + 2) = 0

⇔{x−6=0x+2=0⇔{x=6x=−2⇔{x−6=0x+2=0⇔{x=6x=−2

f, x² - 5x -14 = 0

⇔⇔ x² + 2x - 7x -14 = 0

⇔⇔ x(x + 2) - 7(x + 2) = 0

⇔⇔ (x + 2)(x - 7) = 0

⇔{x+2=0x−7=0⇔{x=−2x=7

a,\(4x^2-49=0\)

\(\Leftrightarrow\left(2x\right)^2-7^2=0\)

\(\Leftrightarrow\left(2x-7\right)\left(2x+7\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}2x-7=0\\2x+7=0\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=7\\2x=-7\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{7}{2}\\x=-\frac{7}{2}\end{cases}}}\)

b.\(x^2+36=12x\)

\(\Leftrightarrow x^2-12x+36=0\)

\(\Leftrightarrow\left(x-6\right)^2=0\)

\(\Leftrightarrow x-6=0\Leftrightarrow x=6\)

c.\(\frac{1}{16x^2}-x+4=0\)

\(\Leftrightarrow\left(\frac{1}{4x}\right)^2-2.\frac{1}{4x}.2+2^2=0\)

\(\Leftrightarrow\left(\frac{1}{4x}-2\right)^2=0\)

........

\(\left(5x-4\right)^2-16x^2=0\)

\(\Leftrightarrow\left(5x-4\right)^2-\left(4x\right)^2=0\)

\(\Leftrightarrow\left(5x-4-4x\right)\left(5x-4+4x\right)=0\)

\(\Leftrightarrow\left(x-4\right)\left(9x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{4}{9}\end{matrix}\right.\)

\(\left(5x-4\right)^2-16x^2=0\\ \Leftrightarrow\left(5x-4\right)^2-\left(4x\right)^2=0\\ \Leftrightarrow\left(5x-4-4x\right).\left(5x-4+4x\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}5x-4-4x=0\\5x-4+4x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{4}{9}\end{matrix}\right.\\ \Rightarrow S=\left\{\dfrac{4}{9};4\right\}\)

     \(5x^2+2y^2-6xy+16x-8y+16=0\)

\(\Rightarrow10x^2+4y^2-12xy+32x-16y+32=0\)

\(\Rightarrow\left(9x^2-12xy+4y^2\right)+\left(24x-16y\right)+16+\left(x^2+8x+16\right)=0\)

\(\Rightarrow\left(3x-2y\right)^2+2.\left(3x-2y\right).4+4^2+\left(x+4\right)^2=0\)

\(\Rightarrow\left(3x-2y+4\right)^2+\left(x+4\right)^2=0\)

\(\Rightarrow\hept{\begin{cases}3x-2y+4=0\\x+4=0\end{cases}\Rightarrow}\hept{\begin{cases}-12-2y+4=0\\x=-4\end{cases}\Rightarrow\hept{\begin{cases}y=-4\\x=-4\end{cases}}}\)

Vậy \(x=y=-4\)