1) \(\Rightarrow10x-16-12x+15=12x-16+11\)

\(\Rightarrow14x=4\Rightarrow x=\dfrac{2}{7}\)

2) \(\Rightarrow4x^2+4x+1-4x^2+13x-3-15=0\)

\(\Rightarrow17x=17\Rightarrow x=1\)

3) \(\Rightarrow\left(3x-1\right)\left(2x-7+6x-5\right)=0\)

\(\Rightarrow\left(2x-3\right)\left(3x-1\right)=0\)

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

2: Ta có: \(\left(2x+1\right)^2-\left(4x-1\right)\left(x-3\right)-15=0\)

\(\Leftrightarrow4x^2+4x+1-4x^2+12x+x-3-15=0\)

\(\Leftrightarrow17x=17\)

hay x=1

$ a/ 12x(x – 5) – 3x(4x - 10) = 120$

`<=>12x^2-60x-12x^2+30x=120`

`<=>-30x=120`

`<=>x=-4`

Vậy `x=-4`

$b/ 9x(x + 4) – 5x(3x + 2) = 112 - 2x(3x + 1)$

`<=>9x^2+36x-15x^2-10x=112-6x^2-2x`

`<=>-6x^2+26x=112-6x^2-2x`

`<=>28x=112`

`<=>x=4`

Vậy `x=4`

$c/ 3x(1 – x) - 5x(3x + 7) = 154 + 9x(5 – 2x)$

`<=>3x-3x^2-15x^2-35x=154+45x-18x^2`

`<=>-32x-18x^2=154+45x-18x^2`

`<=>77x=-154`

`<=>x=-2`

Vậy `x=-2`

1) \(-\frac{2}{3}\left(x-\frac{1}{4}\right)=\frac{1}{3}\left(2x-1\right)\)

\(-\frac{2}{3}x+\frac{1}{6}=\frac{2}{3}x-\frac{1}{3}\)

\(-\frac{2}{3}x-\frac{2}{3}x=-\frac{1}{3}-\frac{1}{6}\)

\(-\frac{4}{3}x=-\frac{1}{2}\)

\(x=\left(-\frac{1}{2}\right):\left(-\frac{4}{3}\right)\)

\(x=\frac{3}{8}\)

a) \(\frac{x}{2}=\frac{y}{5}=\frac{z}{4}\)

Áp dụng tính chất dãy tỉ số bằng nhau , ta có:

\(\frac{x}{2}=\frac{y}{5}=\frac{z}{4}=\frac{2x}{4}=\frac{3y}{15}=\frac{z}{4}=\frac{2x-3y+z}{4-15+4}=\frac{112}{7}=16\)

\(\frac{x}{2}=16=>x=32\)

\(\frac{y}{5}=16=>x=80\)

\(\frac{z}{4}=16=>z=64\)

Câu b) tương tự chỉ cần thay số vào nha bạn

giup mink ai nhanh tick 3 lan nghia la 1 lan tra loi mot lan noi lam rui mot lan noi cam on

\(4^x+5.2^{2x+1}=176\)

\(4^x+5.4^x.2=176\)

\(4^x.\left(1+10\right)=176\)

\(4^x=176:11\)

\(4^x=16\)

\(4^x=4^2\)

\(=>x=2\)

\(4^x+5.2^{2x+1}=176\)
\(\Rightarrow2^{2x}+5.2^{2x}.2=176\)
\(\Rightarrow2^{2x}\left(1+10\right)=176\)
\(\Rightarrow2^{2x}.11=176\)
\(\Rightarrow2^{2x}=16\)
\(\Rightarrow2^{2x}=2^4\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=2\)

\(4^x+5.2^{2x+1}=176\\ 4^x+5.2^{2x}.2=176\\ 4^x+5.4^x.2\\ 4^x+4^x.10=176\\ 4^x.\left(10+1\right)=176\\ 4^x=176:11\\ 4^x=16\\ 4^x=4^2\\ x=2\)

Ta có : 

      12 - 5.2² = -8

 Lại có :

     ( 2.x - 1 )² \(\ge\)0

      | 2.y - x | \(\ge\)0

=>   A = ( 2.x - 1 )² + | 2.y - x | - 8 \(\ge\)- 8

Dấu " = " xảy ra khi : 

           2.x - 1 = 0

           2.y - x = 0

=> x = 0.5; y = 0.25

dễ tích mình rồi mình giải cho