Question

What is the product?

(-2d^2+s)(5d^2-6s)

-10d^4+17d^2s^2-6s^2

-10d^4+17d^4s^2-6s^2

-10d^4+7d^2s-6s^2

-10d^4+17d^2s+6s^2

Answer 1

The answer is -10d⁴ + 17d²s - 6s² and none of the alternatives given is correct. The closest one is D but the signal before 6s² should be negative.

Explanation:

Let's estimate the product, this way:

(-2d^2+s)(5d^2-6s)

(-2d²+ s) * (5d²- 6s)

= -10d⁴ + 12d²s + 5d²s - 6s²

= -10d⁴ + 17d²s - 6s²

The answer is -10d⁴ + 17d²s - 6s² and none of the alternatives given is correct. The closest one is D but the signal before 6s² should be negative.