1- 3, 2) a=1, b=5, c=-4; 3) х(х+3)=180, х^2+3x-180=0, D=9+720=729>0, x1=(-3-27)/2=-15, x2=(-3+27)/2=12
Проверка: х1=-15, х2=-15+3=-12 -15*(-12)=180
х1=12, х2=12+3=15 12*15=180
Ответ: -15 или 12
M/(1,8+2,05) = 9
m = 34,65
n/5 = 63 - 56,08
n = 34,6
k/(8-6,09) = 6
k = 11,46
z/(19,63+0,37) = 8,376
z = 167,52
x/(78,09+21,91) = 0,736
x = 73,6
y/(98,35-83,17) = 7
y = 106,26