(3·10⁻⁵)·(2,5·10²)=(3·2,5)·(10⁻⁵·10²)=7,5·10⁻³=0,0075
1,6у*5=8у
0,8у*10=8у
1,25у*4=у
Pпрямоуг=2*(а+в), 56=2*(a+b), a+b=28, a=28-b
S=a*b, 140=(28-b)*b
b²-28b+140=0
b₁14+2√14, b₂=14-2√14
a₁=14-2√14, a₂=14+2√14
ответ: b₁14+2√14, b₂=14-2√14
a₁=14-2√14, a<span>₂=14+2√14</span>
Х ⋅ 150 = 600 000 : 2000
x+150=600000:2000
x+150=300
x=300-150
x=150
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150×150 = 600 000 : 2000
1000 : х = 1500 : 300
1000:x=5
x=1000:5
x=200
-------------------------
1000:200=1500:300
65 872 + х = 100 ⋅ 10 000
65872+x=1000000
x=1000000-65872
x=934128
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65872+934128=100×10000
278 367 – х = 1 000 000 : 1000
278367-x=1000
x=278367-1000
x=277367
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278367-277367=1000000:1000
Вот и все!