2x²-7x-4<=0
2x²-7x-4=0
D=b²-4ac=49-4×2×(-4)=49+32=81
√D=9
x1=-b-√D/2a = 7-9/4 =-2/4 =-1/2
x2=-b+√D/2a=7+9/4=16/4=4
x є [-1/2;4]
2x²-7x-4<=0
2x²-7x-4=0
D=b²-4ac=49-4×2×(-4)=49+32=81
√D=9
x1=-b-√D/2a = 7-9/4 =-2/4 =-1/2
x2=-b+√D/2a=7+9/4=16/4=4
x є [-1/2;4]