2/3 divided by 4?? I need help po

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

Which expression will have the same sum as 3_8 + 1/4?

Which shows the correct substitution of the values a, b and c from the equation 1=-2x+3x^2+1