5x^2+x+1=0
Let's solve in ℝ: 5x2 + x + 1 = 0
Given the quadratic form ax2 + bx + c, you can calculate the discriminant: Δ = b2 -4ac. Here a = 5, b = 1 and c = 1
Δ = 1 -4·5·1
Δ = 1 -4·5
ⓘ Multiplications are done before additions and subtractions: 4·5 = 20
Δ = 1 -20
ⓘ Start from 1 and move back 20 on the number line, going below zero: 1 -20 = -19
Δ = -19
As Δ < 0, the equation has no real root.
▶Solution: x ∈ ∅