4.
8x^2+10x-3≥0
8x^2+10x-3=0
D=10^2-4*8*(-3)=100+96=196
x1=-10+√196=-10+14=4\16=1\4=0.25
2*8 16
x2=-10-√196=-10-14=-24=-6\4=-1.5
2*8 16 16
8x^2+10x-3=8(x-0.25)(x+1.5)
8(x-0.25)(x+1.5)≥0
+ - +
////////// //////////////////
---------[-1.5]-------------------------[0.25]----------------
Ответ:(-∞;-1.5]U[0.25;+∞)
6.
x^2+7x-60<0<br>x^2+7x-60=0
D=7^2-4*1*(-60)=49+240=289
x1=-7+√289=-7+17=10\2=5
2 2
x2=-7-√289=-7-17=-24\2=-12
2 2
x^2+7x-60=(x-5)(x+12)
(x-5)(x+12)<0<br> + - +
/////////////////////////////////
----------(-12)---------------------------(5)-------------------
Ответ:(-12;5)