rafal: x²+3x-4≤0

magoo: Δ=3²-4*1*(-4)=9+16=25 -b-√Δ -3-5 -8 x₁=---------- = --------- = --------- = -4 2a 2 2 x⊂(-∞; -4)u(1;+∞) -b+√Δ -3+5 x₂ = --------- = -------- = 1 2a 2