give a scheme definition that will determine the sum of 30, 31, 30, 15 and bind the identifier days-in-semester to this sum. be as concise as possible.

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 =