Step-by-step explanation:
1. a² - ( b ² - 2bc + c² ) = a ² - b ² + 2bc - c²
2. 8p² - 18 q²
3. 3ab² - c²d + 3ab - b²c²
4. x² - 2x + 1
I'm sure the measurement was made in grams because:
1. most cell phones weigh between about 100 and 150 grams
2. there's no cell phone that weighs 113 kg, 113 pounds, 113 ounces etc.
