Find three rational number between 3/5 and 7/8​

I’m really confused and need your assist me with this question i’ve never been taught

Asinusoidal function whose frequency is 1/6pi

Determine the vertex form of g(x) = x2 + 2x - 1. which graph represents g(x)? -nw -3-2-1, 1 1 2 3 -3 2- 1 -3- 1 2 3 - 1 2 3