To move it 1 to the left, we make x into (x+1), so we have (x+1)². Conversely, if we wanted to move it to the right, we'd subtract 1 from x. Next, we have to vertically stretch by a factor of 3, meaning that we have to multiply the whole thing (at the current point) by 3, turning our equation into 3(x+1)². Lastly, we must reflect over the x axis, which is the line g(x)=0. If we want to reflect over g(x), we essentially multiply g(x) by -1, making -g(x)=3(x+1)². However, we want to solve for g(x), not -g(x), so we multiply both sides by -1 to end up with -3(x+1)²
