Question

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

25x^2-40x+16
2x^2+x+4
6x^2-2x-20
X^2-2x-4

Answer 1

25x^2 - 40x + 16 = 25x^2 - 20x - 20x + 16 = 5x(5x - 4) - 4(5x - 4) = (5x - 4)(5x - 4)

2x^2 + x + 4 cannot be factored.

6x^2 - 2x - 20 = 6x^2 - 12x + 10x - 20 = 6x(x - 2) + 10(x - 2) = (6x + 10)(x - 2)

x^2 - 2x - 4 cannot be factored using integral coefficients and integral constants.