A) (x²-25)(x²-x-30)≤0
x²-25=(x-5)(x+5)
x²-x-30=0 D=121
x₁=6 x₂=-5
(x-6)(x+5)=0 ⇒
(x-5)(x+5)(x-6)(x+5)≤0
(x-5)(x+5)²(x-6)≤0
-∞_____+____(-5)____+_____5____-_____6_____+_____+∞
x∈(-5)U(5;6).
b) (16x⁴-x²)(-x²-10)≤0
(16x⁴-x²)(x²+10)≥0
x²(16x²-1)(x²+10)≥0
x²(4x-1)(4x+1)(x²+10)≥0
x²≥0 x²+10>0 ⇒
-∞_______+_______-1/4___-____(0)__-____1/4_______+______+∞
x∈(-1/4;1/4).
<span>x²-6x-16<0
</span><span>Сначала решим уравнение.
</span><span>x²-6x-16=0
Д = 36 + 4*16 = 100
х = 6 -10 / 2 = -4 / 2 = -2
х = 6 +10 / 2 = 8
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-2 \\\\\\\\\\\\\\\\\\\\\ 8
(-2 ; 8)
ОТВЕТ </span>(-2 ; 8)<span>
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