Explanation

To find the remainder when 2x² + 1 is divided by x - 1:

Use the Remainder Theorem:

Remainder = f(a), where a is the root of the divisor (x - 1 = 0)

a = 1

Substitute a into the polynomial:

Remainder = f(1)

= 2(1)² + 1

= 2 + 1

= 3