- 3 (2x + 1)(5x - 4) > 0 /:(-3)
(2x + 1)(5x - 4) < 0
2x + 1 = 0
2x = - 1
x = - 0,5
5x - 4 = 0
5x = 4
x = 0,8
+ - +
-------------- - 0, 5 ------------------ 0, 8 ---------------> x
x ∈ ( - 0,5; 0,8)
А³-b³=(a-b)(a²+ab+b²)=(a-b)((a-b)²+3ab)=5(5²+3·6)=215.
Ответ:
Объяснение:
2⁻²+3⁻¹x=0,25
2⁻²+3⁻¹x=1/4
3⁻¹x=2⁻²-2⁻²
x/3=0
x=0
2,25x=5,125-4⁻¹x
9/4 ·x=41/8 -1/4 ·x
9/4 ·x+ 1/4 ·x=41/8
10/4 ·x=41/8
x=41/8 ·4/10=41/20=2 1/20=2,05
4⁻¹x-2⁻²x=8²+x
(2²)⁻¹x-2⁻²x-x=64
2⁻²x-2⁻²x-x=64
0-x=64
x=-64
1)1/a-b + 1/b= (b+a-b)/b(a-b)= a/b(a-b)
2) a/b(a-b) * b/a=ba/ab(a-b)=1/a-b