x - 1 is a factor of 8x² - 7x + m; the value of m is :

1. -1

2. 1

3. -2

4. 2

By factor theorem,

If x - a is a factor of polynomial f(x), then remainder f(a) = 0.

Given,

x - 1 is a factor of 8x² - 7x + m.

⇒ x - 1 = 0

⇒ x = 1.

Substituting x = 1, in 8x² - 7x + m remainder will be zero.

⇒ 8(1)² - 7(1) + m = 0

⇒ 8 - 7 + m = 0

⇒ 1 + m = 0

⇒ m = -1.

Hence, Option 1 is the correct option.