-4x2 +3x +7 = 0
ax2 bx c = 0
a = -4
b = 3
c = 7
Δ = b2-4ac
Δ = 3² - (4 * -4 * 7)
Δ = 9 - (4*-28)
Δ = 9 - (-112)
Δ = 121 Δ > 0
-4x2+3x+7=0
x = -b ∓ √Δ 2a
x' = -3 - √121 2*-4 = -3 - 11.0 -8 = -14.0 -8 = 1.75
x" = -3 + √121 2*-4 = -3 + 11.0 -8 = 8.0 -8 = -1.0
x' = 28.0
x" = -16.0
S = {x ∈ R / x' = 28.0, x" = -16.0 }