Tìm x , biết: (a) 1 /2 − x = 3/ 4

Tìm \(x\), biết:

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

(b) \(\frac{1}{4}{\left( {x - 3} \right)^2} - \frac{9}{{16}} = 0\).