What's the answer to 2 + 3a + 9a? 2+2a? or 14a?

What is the difference between the predicted value and the actual value

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?