Final answer:
To factor the trinomial 12r^2 + 7rs - 10s, we need to find two numbers that multiply to give the constant term (-10) and add up to give the coefficient of the middle term (7). These numbers are 10 and -1.
Step-by-step explanation:
To factor the trinomial 12r^2 + 7rs - 10s, we need to find two numbers that multiply to give the constant term (-10) and add up to give the coefficient of the middle term (7). These numbers are 10 and -1.
Therefore, we can rewrite the trinomial as (3r + 10s)(4r - s).
So the correct answer is option a.) (4r + 5s)(3r - 2s).