Answer
(s-15t)(s+5t)
Work Step by Step
Given the polynomial
$s^{2}$ - 10st - $75t^{2}$
*** We break of the middle term into two factors that add to give -10 and multiply to give -75. The two numbers are -15 and +5.
$s^{2}$ - 15st + 5st - $75t^{2}$
We take the GCD of the first two and the GDC of the last two terms.
s(s-15t) +5t(s-15t)
We take (s-15t) and factor it out which gives us.
(s-15t)(s+5t)
