Δ=0
a) 5x²-7x+m=0
Δ=(-7)²-4×5×m=0
49-20m=0
m=49/20
b)-x²+12x+m=0
Δ=12²-4×(-1)×m=0
144+4m=0
m=-144/4=-36
c)3x²-6x+m-2=0
Δ=(-6)²-4×3×(m-2)=0
36-12m+24=0
m=60/12=5
d)x²+4x+m-1=0
Δ=4²-4×1×(m-1)=0
16-4m+4=0
m=20/4=5
e)
25x²+40x+m=0
Δ=40²-4×25×m=0
1600-100m=0
m=1600/100=16
f)x²-10x+m=0
Δ=(-10)²-4×1×m=0
100-4m=0
m=100/4=25
