x^2-y^2-10x+25=x^2-10x+25-y^2=(х-5)^2-у^2=(х-у-5)(х+у-5)
А6 = а1 + 5d = 2 + 5·(-3) = 2 - 15 = -13
S6 = (2 -13)·6/2 = -11·3 = -33
1) sinx=√3/2
x=(-1)^n*arcsin√3/2+πn n∈Z
x=(-1)^n*π/2+πn n∈Z
2) tgx/3=1/√3
tgx/3=√3/3
x/3=arctg√3/3+πn n∈Z
x/3=π/6+πn n∈Z
x=π/2+3πn n∈Z
-7x-28=-3x-52
-7х + 3х = -52 + 28
-4х = -24
х = 6
<span>5(х-1) - 4(х+2)=3
5x - 5 - 4x - 8 = 3
x = 16
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