Convert the following to standard notation.
1.5 x 10

What number produces an irrational number when multiplied by -1.25

Bring the fraction a/a-4 to a denominator of 16-a^2

Acomputer store buys a computer system at a cost of $370.80. the selling price was first at $ 618, but then the store advertised a 20 % markdown on the system. answer parts a and b. a. find the current sale price.