Move right part of the equation to
left part with negative sign.
The equation is transformed from
$$4 b^{2} = 144$$
to
$$4 b^{2} - 144 = 0$$
This equation is of the form
a*b^2 + b*b + c = 0
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$b_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$b_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 4$$
$$b = 0$$
$$c = -144$$
, then
D = b^2 - 4 * a * c =
(0)^2 - 4 * (4) * (-144) = 2304
Because D > 0, then the equation has two roots.
b1 = (-b + sqrt(D)) / (2*a)
b2 = (-b - sqrt(D)) / (2*a)
or
$$b_{1} = 6$$
$$b_{2} = -6$$