1) 7/5 от 41=41*7/5=57,4
2) 3/4 от 5/3=5/3*3/4=5/1*1/4=5/4=1,25
3) 7/2 от 75= 75*7/2=262,5.
1)
92 - 10m
2)
m≤9
1;2;3;4;5;6;7;8;9
cos2x+sin²x = 0,75
cos²x - sin²x + sin²x = 0.75
cos²x = 0.75
cosx = ±√0.75 = ±0.5√3
1) cosx = -0.5√3
x₁ = 5π/6 + 2πn
x₂ = -5π/6 + 2πn
n =1 x₁ = (2 + 5/6) π x∉[π; 5π/2]
x₂ = (2- 5/6) π = 7π/6 x∈[π; 5π/2]
n =2 x₁ = (4 + 5/6) π x∉[π; 5π/2]
x₂ = (4- 5/6) π x∉[π; 5π/2]
2) cosx = 0.5√3
x₁ = π/6 + 2πn
x₂ = -π/6 + 2πn
n =1 x₁ = (2 + 1/6) π = 13π/6 x∈[π; 5π/2]
x₂ = (2 - 1/6) π = 11π/6 x∈[π; 5π/2]
n =2 x₁ = (4 + 1/6) π x∉[π; 5π/2]
x₂ = (4- 1/6) π x∉[π; 5π/2]
Ответ: x = 7π/6; 11π/6; 13π/6
400-5x+20=370
-5x+420=370
-5x+50=0
-5x=-50
x=-10
Вроде так ,но не факт
1)57:19*1=3
2)33:11*3=9
3)42:6*7=49
а)80*5:1=400
б)420*30:7=1800
в)125*23:25=115