Question

Tìm x:

a) 2x + 11 \(⋮\) 2x - 3

b) [(2x - 1)² + 3x + 9] \(⋮\) 2x - 1

c) [(3x - 4)²⁰¹⁶ + 3x + 9] \(⋮\)3x - 4

Answer 1

a: \(\Leftrightarrow2x-3+14⋮2x-3\)

\(\Leftrightarrow2x-3\in\left\{1;-1;2;-2;7;-7;14;-14\right\}\)

hay \(x\in\left\{2;1;\dfrac{5}{2};\dfrac{1}{2};5;-2;\dfrac{17}{2};-\dfrac{11}{2}\right\}\)

b: \(\Leftrightarrow3x+9⋮2x-1\)

\(\Leftrightarrow6x+18⋮2x-1\)

\(\Leftrightarrow2x-1\in\left\{1;-1;3;-3;7;-7;21;-21\right\}\)

hay \(x\in\left\{1;0;2;-1;4;-3;11;-10\right\}\)

c: \(\Leftrightarrow3x+9⋮3x-4\)

\(\Leftrightarrow3x-4\in\left\{1;-1;13;-13\right\}\)

hay \(x\in\left\{\dfrac{5}{3};1;\dfrac{17}{3};-3\right\}\)