Select all the expressions that cannot be factored using integral coefficients and integral constants.

a. 25x2 - 40x + 16
b. 2x2 + x + 4
c. 6x2 - 2x - 20
d. x2 - 2x - 4

The expressions that cannot be factored using integral coefficients and integral constants is the below:
b. 2x2 + x + 4
d. x2 - 2x - 4

For a. 25x2 - 40x + 16 the factors are (5x – 4) (5x – 4)
For c. 6x2 - 2x - 20 the factors are (2x - 4) (3x + 5)

Multiplication property of zero

If you make you answer for clear i can answer it : )