What is -5 5/8 + 3 1/2

Which of the following contains a variable?

One astronomical unit (1 au) is about 1.496 alt tag missing. kilometers. if you wrote this number of kilometers in regular decimal notation (for example, 528 and 3,459 are written in regular decimal notation), how many zeros would your number have?

Asquare and an equilateral triangle have the same perimeter. each side the triangle is 4 inches longer than each side of the square. what is the perimeter of the square