x2 – 5x + 4

To factor this quadratic equation, we'll look for two numbers that multiply to 4 (the last term) and add up to -5 (the middle term). These two numbers are -1 and -4.

So, we can rewrite the quadratic equation as:

x^2 - 1x - 4x + 4

Now, we'll factor by grouping:

x(x - 1) - 4(x - 1)

Finally, we have:

(x - 4)(x - 1)