Can someone tell me how to complete a square ?? I have a picture as an example

What is the shape of the height and weight distribution

The probability that an adult possesses a credit card is .70. a researcher selects two adults at random. by assuming the independence, the probability that the first adult possesses a credit card and the second adult does not possess a credit card is:

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.