Final answer:
The sum of (−9x + 3y) and (−3x + 5y) is −12x + 8y, which is achieved by adding each set of like terms together.
Step-by-step explanation:
To find the sum of (−9x + 3y) and (−3x + 5y), we simply add the like terms. The x-terms are −9x and −3x, and the y-terms are 3y and 5y. Therefore, the sum is:
(−9x + 3y) + (−3x + 5y) = (−9x − 3x) + (3y + 5y) = −12x + 8y.
This expression represents the combined sum of the two polynomial expressions.