Answer
$(0,-1)$
Work Step by Step
$y_1+y_2$ will be above $y_1$ by $y_2$ if $y_2$ is positive. $y_1+y_2$ will be below $y_1$ by $y_2$ if $y_2$ is negative.
Hence if the given points are on the original graphs, then $(0,1-2)=(0,-1)$ is on $y_1+y_2.