3*(2х-4)=18х-5
6х-12=18х-5
6х-18х=12-5
-12х=7
х=-7:12
-3x • (x - 4) = -3x • x - 3x • (-4) = -3x² + 12x
5x²y • (x² - y) = 5x²yx² - 5x²y • y = 5x⁴y - 5x²y²
(7x - 2) • (x - 5) = 7x² - 35x - 2x + 10 = 7x² - 37x + 10
Ответ:
17. 1 17/84.
18. 7/108.
Объяснение:
17.
9 9/28 - (4 5/21 - x) = 6 2/7
9 9/28 - 4 5/21 + x = 6 2/7
х = 6 2/7 + 4 5/21 - 9 9/28
х = 6 24/84 + 4 20/84 - 9 27/84
х = 1 17/84
Ответ: 1 17/84.
18.
3 5/36 - (1 31/54 - х) = 1 17/27
3 5/36 - 1 31/54 + х = 1 17/27
3 15/108 - 1 62/108 + х = 1 68/108
х = 1 68/108 + 1 62/108 - 3 15/108
х = 3 22/108 - 3 15/108
х = 7/108
Ответ: 7/108.