Formula deltei: Δ = b²-4ac
1) 2x²+10x +5 = 0, a = 2, b = 10, c= 5
Δ = 10²-4*2*5 = 100 - 40 = 60
2) -3x²+6x+1 = 0 , a = -3, b = 6, c = 1
Δ = 36 - 4*(-3)*1 = 36+12 = 48
3) 4x²-7x²+2 = 0
-3x²+0x+2 = 0 , a = -3, b = 0, c= 2
Δ = 0² - 4*(-3)*2 = 0 +24 = 24
