jvgcuchoa - (-10) + √(-10)^2-4.2.2   /  2.2
10+84 / 4
94/4 = 23,5

PauloBarros ∆ = b^2-4ac; ∆ = (-10)^2-4.2.2; ∆ = 100-16; ∆= 84; √∆ = √4.√21; √∆ = 2√21; x= - (-10)+/- 2√21/ 2.2;x = 10 +/- 2√21/4; {Resp.: x = (5+√21)/2, x = (5-√21)/2}