3x + 4y = 7
5x - 4y = 9
------------------- +
8x = 16
x = 2
y = (7 - 3x)/4 = (7 - 6)/4 = 1/4
ОТВЕТ
( 2; 1/4)
См. фото. ........... ..........
(4x-9x²)/(10-x)≥0 ОДЗ: 10-x≠0 x≠10
4x-9x²≥0 x(4-9x)≥0 x≥0 x≤4/9 x∈[0;4/9]
10-x≥0 x≤10
x(4-9x)/(10-x)≥0
-∞_____-____0____+____4/9____-____10____+_____+∞
x∈[0;4/9]∨(10;+∞).