1
3x^2+5x-37≥(x+9)(x-4)
3x²+5x-37-x²+4x-9x+36≥0
2x²-1≥0
(√2x-1)(√2x+1)≥0
x=1/√2 U x=-1/√2
x∈(-∞;-1/√2] U [1/√2;∞)
2
2x^4-3x^2+1≥0
x²=a
2a²-3a+1≥0
D=9-8=1
a1=(3-1)/4=1/2 U a2=(3+1)/4=1
a≤1/2⇒x²≤1/2⇒(x-1/√2)(x+1/√2)≤0⇒-1/√2≤x≤1/√2
a≥1⇒x²≥1⇒(x-1)(x+1)≥0⇒x≤-1 U x≥1
x∈(-∞;-1] U [-1/√2;1/√2] U [1;∞)
3
(x+4)(x+2)^2(x-1)^3(x-5)≥0
x=-4 x=-2 x=1 x=5
_ + + _ +
---------[-4]--------------[-2]------------[1]------------[5]-------------------
x∈[-4;1] U [5;∞)