factor 4x^2-8x+16
Let's factor in ℝ: 4x2 -8x + 16
We factor out 4, the greatest common divisor of the coefficients: 4x2 -8x + 16 = 4·(x2 -2x + 4)
Given the quadratic form ax2 + bx + c, you can calculate the discriminant: Δ = b2 -4ac. Here a = 1, b = -2 and c = 4
Δ = (-2)2 -4·1·4
ⓘ Powers are computed before multiplications, additions and subtractions. An integer power is a repeated product: (-2)2 = (-2)·(-2) = 4
Δ = 4 -4·4
ⓘ Multiplications are done before additions and subtractions: 4·4 = 16
Δ = 4 -16
ⓘ Start from 4 and move back 16 on the number line, going below zero: 4 -16 = -12
Δ = -12
As Δ < 0, the equation has no real root.
Factor found: x2 -2x + 4
▶Factored expression:   4·(x2 -2x + 4)