X² - 3x - 5 = 0
D = 9 + 20 = 29
x1 = (3-√29)/2
x2 = (3+√29)/2
1) 1/x1 + 1/x2 = 2/(3-√29) + 2/(3+√29) = (6+2√29+6-2√29)/(9-29) = 12/(-20) = -3/5 = -0,6
2) x1² + x2² = (3-√29)² + (3+√29)² = 9 -6√29 + 29 + 9 + 6√29 + 29 = 76
3) x1/x2 + x2/x1 = (x1² + x2²)/(x1*x2) = 76/((3-√29)(3+√29)) = 76/(9-29) = 76/(-20) = -19/5 = -3,8
1. 611
2. 669
3. 65539
4. 460
5.
6. 31
7. 748-695=53
8. 283 метра
9. 2999, 3000, 3001
25:5*3=15
3 1/3:2=10/3:2=10/3*1/2=5/3
<span> 2 1/2:1/10+9/10=5/2*10+9/10=25 9/10</span>
<span><span>х:6/17=3 2/5</span></span>
<span><span>х=17/5*6/17</span></span>
<span><span>х=6/5=1 1/5</span></span>