6+(-7) can anybody tell me how this works

Which ordered pair (c, d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

Venita is sewing new curtains. the table below shows the relationship between the number of stitches in a row and the length ofthe row. sewingnumber of stitches length (cm)51 131532024306what is the relationship between the number of stitches and the length? othe number of stitches istimes the length. o. the number of stitches is 3 times the length.

Two angles are complementary. the larger angle is 36 more than the smaller angle. what is the measure of the larger angle?