Find the distance between the points (3,8) and (-1,9)

Which of the following is the equation that says that the product of a number and ten is equal to 20 percent of that number ? a) 10n= 2.0n b) 10+n=.20n c) n+ .20n=10 d) 10n=0.20n

Anyone know? will mark brainliest if correct

The vertex of this parabola is at (-2,-3). when the x-value is -1, the y-value is -5. what is the coefficient of the squared expression in the parabola's equation?