Tìm x :

----- Nội dung ảnh -----
1) Tìm dx : a) \( (x+2)(6x+1)+7=(2x+9)(3x+2) \)
b) \( \frac{2}{3} ( \beta - 1)^{2} - \frac{3}{2} (2x+3)^{2} = \frac{1}{4} (x-3)(4+x) - 3x(2+1) \)