Answer
(a) Both equations have the dimensions $\frac{kg\cdot m}{s^2}$
(b) The force unit newton has the dimensions $\frac{kg\cdot m}{s^2}$
Work Step by Step
(a) We can analyze the dimensions of $ma$:
$kg \times \frac{m}{s^2} = \frac{kg\cdot m}{s^2}$
We can analyze the dimensions of $kx$:
$\frac{kg}{s^2} \times m = \frac{kg\cdot m}{s^2}$
We can see that the dimensions are equivalent.
(b) The force unit newton has the dimensions $\frac{kg\cdot m}{s^2}$