Question

помогите решить 3 и 4

Answer 1

3. A U B = (0; 10]

A∩B = [3; 7)

4.
5 - 7x > 12
x² > 64

7x < -7
x > 8 или x < -8

x < -1
x > 8 или x < -8

x∈ (-∞; -8)

Answer 2

A∪B=(0;10]
A∩B=[3;7)

{(5-7x)/6>2
{64-x²<0
1)(5-7x)/6-2>0
(5-7x-12)/6>0
(7x+7)/6<0
7x+7<0
7x<-7
x<-1
2)(8-x)(8+x)<0
x=8 x=-8
             _                +         +       _
----------------(-8)-------(-1)------(8)--------------
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x∈(-∞;-8)