Решите неравенства 1) (х -5)(х-1,5) < 0 2) 0,4х (7-х)(х-0,8)《 0 《- больше либо равно
1) (x-5)(x-1.5)∠0 x²-1.5x-5x+7.5∠0 x²-6.5x+7.5∠0 a=1 b=-6.5 c=7.5 x1/2=(-b+-√(b²-4ac))/2a x1/2=(6.5+-√(42.25-30))/2=(6.5+-√12.25)/2=(6.5+-3.5)/2 x1=(6.5-3.5)/2=3/2 x1=1.5 x2=(6.5+3.5)/2=10/2 x2=5 2) 0.4(7-x)(x-0.8)≤0 0.4(7x-5.6-x²+0.8x)≤0 0.4(-x²+7.8x-5.6)≤0 -0.4x²+3.12x-2.24≤0 -0.4x²+3.12x-2.24≤0 a=-0.4 b=3.12 c=-2.24 x1/2=(-b+-√(b²-4ac))/2a x1/2=(-3.12+-√(9.7344-3.584))/(-0.8)=(-3.12+-√6.1504)/(-0.8) x1/2=(-3.12+-2.48)/(-0.8) x1=(-3.12-2.48)/(-0.8)=-5.6/(-0.8) x1=7 x2=(-3.12+2.48)/(-0.8)=-0.64/(-0.8) x2=0.8 x1≤7 x2≤0.8