What is the pH of a 6.4x10-10 M OH- solution? ph = ?

Please help, and show me how to do this.
Thank you

Complete the equation of the line through (−10,3) and (−8,−8). use exact numbers.

When the solutions to each of the two equations below are graphed in the xy-coordinate plane, the graphs of the solutions intersect at two places. write the y-cordninates of the points of intersection in the boxes below in order from smallest to largest. y=2x y=x^2-3

2y= 3 2 x−2 y = − 1 3 x + 1 y=− 3 1 x+1