mohon bantu ikut jalan

f(x) = (x - 1/2)(x - 3/5)
f(1) = m
20m = ...?

f(1) = (1 - 1/2)(1 - 3/5)
f(1) = (2/2 - 1/2)(5/5 - 3/5)
f(1) = 1/2 x 2/5
f(1) = 1/5

f(1) = m
m = 1/5

20m = 20 x 1/5 = 4

jawaban D