2t-(17-(t-7))=3(t-8)
2т-(17-т+7)=3т-24
2т-17+т-7=3т-24
3т-24=3т-24
Sin2x+4cos²x=1
2sinxcosx+4cos²x=sin²x+cos²x
sin²x-2sinxcosx-3cos²x=0 (:cos²x≠0)
tg²x-2tgx-3=0
tgx=y;y²-2y-3=0;y₁=-1;y₂=3
1) tgx=-1
x=-π/4+πn,n∈Z
2) tgx=3
<span>x=arctg3+πk,k∈Z.</span>
25 - 30x + 9x^2 - 17x = 9x^2 - 6x + 12
25 - 30x + 9x^2 - 17x - 9x^2 + 6x - 12 = 0
- 41x + 13 = 0
- 41x = - 13
x = 13/41