Answer
See below
Work Step by Step
Find $C$ by applying the law of sines:
$$\frac{\sin C}{c}=\frac{\sin B}{b}\\\sin C=\frac{\sin B}{b}\times c\\\arcsin(\sin C)=\arcsin(\frac{\sin B}{b}\times c)\\C=\arcsin(\frac{\sin B}{b}\times c)\\C=\arcsin (\frac{\sin 56^\circ}{17}\times 14)\approx43^\circ$$
The sum of the angles of the triangle is $180^\circ$
$$A+B+C=180^\circ\\B=180^\circ-B-C\\B=180^\circ-56^\circ-43^\circ\\B=81^\circ$$
Use the law of sines:
$$\frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{y\sin C}$$
We obtain: $\frac{a}{\sin A}=\frac{c}{\sin C}\\a=\frac{c}{\sin C}\times\sin A=\frac{14}{\sin 43^\circ}\times\sin 81^\circ\approx 20.27$
