to add integers with like signs, add the integers with unlike sign's subtract the integers and copy the sign of the integers with greatest value give me a two example​

Find the value of a. the diagram is not to scale. a quadrilateral is drawn. the upper and lower sides are parallel. the interior angle in the upper left corner is labeled a degrees. the angle in the upper right corner is labeled 113 degrees. the angle in the lower right corner is labeled b degrees. the angle in the lower left corner is labeled 36 degrees. a. 36 b. 144 c. 54 d. 126

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Solve x+3y=6 and 4x-6y=6 by elimination . show work !