5x-7+x=4x-9
6x-4x=-9+7
2x=-2
x=-2:2
x=-1
1. α=(270°+45°) = 315° β=(90°+45°) = 135°
2. α=0 или α=2π , β = π
3. α = 60° + 360°*n , β= 120°+360°*n, где n=1,2,3,4... (n∈Z)
4. α= 5π/6 +2πn , β = 7π/6 +2πn, n ∈ Z
6,78+7,45-3,86=10.37
0.6+6.08+0.82=7.5
3*3/4 * 5* 3/5 = 15/4 * 28/5=21