7sin²x - 14sinx + 2 = -5 Get 0 on the right by adding 5 to both sides: 7sin²x - 14sinx + 7 = 0 Since every term is divisible by 7, we divide through by 7: sin²x - 2sinx + 1 = 0 Factor as a trinomial: (sinx-1)(sinx-1) = 0 (sinx-1)² = 0 sinx-1 = 0 sinx = 1 x = p/2 + 2p∙n Edwin