Can anyone help me explain what’s wrong with Billy’s answer.

Remmi wrote the equation of the line y=⅓(x+2) he solved for x and got x=3y-2 which of the following is an equivalent equation for x? a.x=y-11/3 b.x=y+7/3 c.x=3(y-⅔) d.x=3(y+⅔)

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?

What is the result of adding the system of equations? 2x+y=4 3x-y=6