यदि AB||CD है तो x का मान ज्ञात कीजिये

The lines AB and CD are parallel, and they are intersected by a transversal line. The angles $(3x + 15^\circ)$ and $(2x + 30^\circ)$ are consecutive interior angles (also known as same-side interior angles).

When two parallel lines are cut by a transversal, the consecutive interior angles are supplementary, meaning their sum is $180^\circ$.

Combine the terms with $x$ and the constant terms.

Subtract $45^\circ$ from both sides.

Divide by 5.

The value of $x$ is $\boxed{\text{27}}$.