Simplify the expression. 1.7m2 + 6.5n – 4n + 2.5m2 – n

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

If the wwight of a package is multiplied by 7/10 the result is 65.8 find the weight of the package

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?