Cos(π/4 - x) > √3/2
cos(x - π/4) > √3/2
- arccos(√3/2) + 2πn < x - π/4 < arccos(√3/2) + 2πn, n∈z
- π/6 + 2πn < x - π/4 < π/6 + 2πn, n∈Z
- π/6 + π/4 + 2πn < x < π/6 + π/4 + 2πn, n∈Z
π/12 + 2πn < x < (5π)/12 + 2πn, n∈Z
2*x+3/4+x/3=x+1/2
x*(2+1/3-1)=1/2-3/4
x*4/3= - 1/4
x= - 3/16
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2x²-4x-14=(x-1)²
2x²-4x-14=x²-2x+1
x²-2x-15=0
По теореме Виета:
x₁=-3,x₂=5
Ответ:-3;5.