We have the following equation: x2 + 4x = - (y2 - 20) Let's review step by step: step 1: x2 + 4x = -y2 + 20 Answer: OK step 2: x2 + 4x + 4 = -y2 + 20 - 4 Answer: Wrong The correct step is: x2 + 4x - 4 = -y2 + 20 - 4 Or equivalently: x2 + 4x + 4 = -y2 + 20 + 4 Answer: he did make an error in his work in step 2
Step-by-step explanation: 6% is equal to 0.06, so you can add multiply the price of the item by 1.06 because that is the base cost plus the tax. Then you get $100.70.