1. Она пролетит 120 метров. Решается с помощью пропорции
8×45/3=120м
<span>(х+1)*(x²-10х+25) = 7(х-5),
(х+1)(х-5)</span>² = 7(х-5),
(x+1)*(x-5)²-7(x-5) = 0,
(x-5)*((x+1)*(x-5)-7) = 0,
x-5 = 0,
x₁ = 5,
(x+1)*(x-5)-7 = 0,
x²-5x+х-5-7 = 0,
x²-4x-12 = 0,
D = (-4)² - 4*1*(-12) = 16 + 48 = 64,
x₂ = (4 + 8)/2*1 = 12/2 = 6,
x₃ = (4 - 8)/2*1 = -4/2 = -2.
Ответ: x₁ = 5 x₂ = 6 x₃ = -2.
1/ 6 = x/22 | * 66
11 = 3x
x = 11/3
1/6 = 3,(6)/22
1/6 = x/33 | * 66
11 = 2x
x = 5 ,5
1/6 = 5,5/33
1/6 = x/440
x = 73.(3)
1/6 = 73,(3)/440
31.
97-88-39+42=12
32.
49÷(84-91)=49÷(-7)=(-2)
33.
(123-49-83)÷(186-195)=-9÷9=1
34.
5×(74-93)=5×9=45
35.
(12+63-36)÷(-13)=39÷(-13)=(-3)
36.
29/30-5/18×6/25=29/30-1/15=29/30-2/30=27/30
37.
18/7×(4/9+15/18)=18/7×(8/18+15/18)=18/7×23/18=23/7=3 2/7
38.
8/5×3/4+11/8=6/5+11/8=48/40+55/40=103/40=2 23/40
39.(-1/3)×6/5-5/6×3/25=-2/5-1/10=-4/10+(-1/10)=(-5/10)
40.
18/7×4/9+15/14=8/7+15/14=16/14+15/14=31/14=2 3/14