А) (3х)/(х + 4) = 8/(х + 4)
3х = 8
х = 8/3
б) 10/х = 7-х
10 = 7х -х²
х² - 7х + 10 = 0
D = 49 - 40 = 9
x₁ = (7 + 3)/2 = 5
x₂ = (7 - 3)/2 = 2
в) (х + 3)/х = (2х + 10)/(х - 3)
х² - 9 = 2х² + 10х
х² + 10х + 9 = 0
D = 100 -36 = 64
x₁ = (-10 + 8)/2 = -1
x₂ = (-10 - 8)/2 = -9