I recommend that instead of decimal numbers you enter an expression using sqrt() to indicate a square root. For example instead of 1.4142 you would enter sqrt(2) .

The distance between the points $(2,6)$ and $(3,8)$ is . The distance between the points $(9,5)$ and $(2,7)$ is . The distance between the points $(-4,6)$ and $(5,7)$ is . The distance between the points $(-8,-6)$ and $(-2,-5)$ is .
Hint: Don't try to memorize a formula. Draw a picture showing the two points in a rectangular coordinate system and apply the Pythagorean Theorem.