Resposta :
a = 1
b = -(k+4)
c = 4k
Δ = [-(k+4)]² - 4.1.4k
Δ = k²+8k+16-16k
Δ = k²-8k+16
Δ = (k-4)²
x = -[-(k+4)]+/-\/(k-4)²/2
x = [(k+4)+/-(k-4) ]/2
x' = [k+4+k-4]/2 --> x' = 2k/2 --> x' = k
x" = [k+4-(k-4)]/2 --> x" = [k+4-k+4]/2 --> x" = 8/2 --> x" = 4
S: {k; 4}
b = -(k+4)
c = 4k
Δ = [-(k+4)]² - 4.1.4k
Δ = k²+8k+16-16k
Δ = k²-8k+16
Δ = (k-4)²
x = -[-(k+4)]+/-\/(k-4)²/2
x = [(k+4)+/-(k-4) ]/2
x' = [k+4+k-4]/2 --> x' = 2k/2 --> x' = k
x" = [k+4-(k-4)]/2 --> x" = [k+4-k+4]/2 --> x" = 8/2 --> x" = 4
S: {k; 4}