I need help finding a equation

Find the solutions for a triangle with a =16, c =12, and b = 63º

Follow these steps using the algebra tiles to solve the equation −5x + (−2) = −2x + 4. 1. add 5 positive x-tiles to both sides and create zero pairs. 2. add 4 negative unit tiles to both sides and create zero pairs. 3. divide the unit tiles evenly among the x-tiles. x =

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.