5x²+mx-12=0
5× (-2)²+m × (-2) -12=0
20-2m-12=0
8=2m
m=4
5x²+4x-12=0
a=5
b=4
c=-12
Δ=16+4×5×12=14+240=256
x₁,₂=(-4+/-√256/2)/10=(-4+/-16)/10
x₁=(-4+16)/10=12/10=6/5 =1,2
x₂=-2
2.Inlocuiti ecuatia de gradu II printr-o ecuatie de gradu II redusa si enumerati coeficienti p si q ai ecuatiei
2x²-5x+1=0 :2
x²-5/2 x+1/2=0
x²-2,5 x+0,5=0
p=5/2 =-2,5
q=1/2=0,5