Here's how to solve the problem:
Part (a): Find the value of x.
Given: AB∥CD and OE⊥OF.
This means ∠EOF=90∘.
Step 1: Draw a line through O parallel to AB and CD. Let this line be MN.
Since MN∥AB, ∠AEO and ∠EOM are alternate interior angles.
∠EOM=∠AEO=50∘
Step 2: Since MN∥CD, ∠OFC and ∠FOM are alternate interior angles.
∠FOM=∠OFC=x