Find sin B.
\(\dfrac{7}{\sin B} = \dfrac 6{\sin 30^\circ}\\ 6\sin B = 7\sin 30^\circ\\ 6 \sin B = \dfrac72\)
Now this is a linear equation in sin B, so you can solve for sin B by dividing by 6 on both sides.
No matter B is acute or not, sin B is the same.
