1,2mn−3n<span>
0,6ku−0,6u</span>
b−bk
-4 1/8+ 89/8= -4 1/8 + 11 1/8= 7 2/8 = 7.25
.........................
<span>X=4 x=9
+ _ +
————(4)————-(9)—————
x(-;4) U (9;)</span><span>(х-4)(х-9)>0;1)х-4>0;х>4. 2)х-9>0;х>9. Вдповдь: (-;4)(9;+)</span>
<span>|х2+х-20|≤х2+х-20
</span>х2+х-20>0
d=1+80=81
X12=(-1+-9)/2=-5 4
(X-4)(X+5)>0
=========-5=======4=======
+++++++++ -------------- +++++++
1/при x<-5 x>4 |х2+х-20|=(х2+х-20)
2/x=(-5 4) |х2+х-20|=-(х2+х-20)
1/ х2+х-20≤х2+х-20
всегда равенство
2. -(х2+х-20)≤ х2+х-20
2x2+2x-40≥0
x2+x-20≥0
x=-5 4
ответx=(-oo -5]U[4 +oo)