Х² + 2х - 15 = 0
D = 4 - 4 * 1 * (-15) = 4 + 60 = 64 = 8²
x1 =(-2+8) / 2 = 3
x2 = ( -2 - 8) / 2 = -5
Ответ: х = 3; х = -5
<span> (lg900-2)/(2lg0,5+lg100)=(lg9+lg100-2)/(lg0.25*100)=lg9/lg25=2lg3/2lg5=lg3/lg5=log5 3</span>
3*П\6+4*3П\4+П\3= П\2+3П+П\3= 23П\6