(2х-3)/(х+5) = (4х-9)/(3х-1) - это пропорция
(2х - 3) · (4х - 9) = (х + 5) · (3х - 1) - свойство пропорции
8х² - 12х - 18х + 27 = 3х² + 15х - х - 5
8х² - 30х + 27 = 3х² + 14х - 5
(8х² - 3х²) - (30х + 14х) + (27 + 5) = 0
5х² - 44х + 32 = 0
D = b² - 4ac = (-44)² - 4 · 5 · 32 = 1936 - 640 = 1296
√D = √1296 = ±36
х = (-b±√D)/2a
х₁ = (44-36)/(2·5) = 8/10 = 4/5 = 0,8
х₂ = (44+36)/(2·5) = 80/10 = 8
Ответ: 0,8; 8.
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(2х-3)/(х+5) = (4х-9)/(3х-1) - это пропорция
(2х - 3) · (4х - 9) = (х + 5) · (3х - 1) - свойство пропорции
8х² - 12х - 18х + 27 = 3х² + 15х - х - 5
8х² - 30х + 27 = 3х² + 14х - 5
(8х² - 3х²) - (30х + 14х) + (27 + 5) = 0
5х² - 44х + 32 = 0
D = b² - 4ac = (-44)² - 4 · 5 · 32 = 1936 - 640 = 1296
√D = √1296 = ±36
х = (-b±√D)/2a
х₁ = (44-36)/(2·5) = 8/10 = 4/5 = 0,8
х₂ = (44+36)/(2·5) = 80/10 = 8
Ответ: 0,8; 8.