Answer:
9x2-y2 + 8xy -1
Step-by-step explanation:
9x2 -1 - y2 +8xy
9x2-y2 + 8xy -1
The sum of these two given quadratic function is (9x² - y² + 8xy - 1).
A quadratic function is a function that has a variable with the highest power of the variable is 2.
A quadratic function may contain more than one variable. However, the highest degree of any variable must be 2.
Given, two function are 8x² + 12 - y² and x² - 13 + 8xy.
Therefore, the sum of these two given function are:
(8x² + 12 - y²) + (x² - 13 + 8xy)
= 8x² + x² - y² + 8xy +12 - 13
= 9x² - y² + 8xy - 1
Learn more about quadratic function here: https://brainly.com/question/5975436
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