a, \(x^2-6x+9=x^2-2.3.x+3^2=\left(x-3\right)^2\)
b, \(4y^2+y+\dfrac{1}{16}=\left(2y\right)^2+2.\dfrac{1}{4}.2y+\left(\dfrac{1}{4}\right)^2=\left(2y+\dfrac{1}{4}\right)^2\)
a)\(x^2\)-6x+9=\(\left(x-3\right)^2\)
b)\(4y^2+y+\dfrac{1}{16}=\left(2y+\dfrac{1}{4}\right)\)