Mark M. answered 01/24/21
Retired math prof. Very extensive Precalculus tutoring experience.
Multiply the numerator and denominator of 8 / (tanx + secx) by tanx - secx to get:
8(tanx - secx) / (tan2x - sec2x)
Since tan2x + 1 = sec2x, tan2x - sec2x = -1.
So, we have 8(tanx - secx) / (-1) = 8(secx - tanx)