Answer:
-2y⁴ - 5y² + 42
Explanation:


Here First terms are

Outer terms are y² and 7 ==> (y²)(7) = 7y²
Inner terms are 6 and -2y² ==> 6(-2y²) = -12y²
Last terms are 6 and 7 ==> 6.7 = 42
So result is obtained by adding all these terms
-2y⁴ + 7y² - 12² + 42 ==> -2y⁴ - 5y² + 42