Question

resolva a equaçao:
cx,2 = 21

Answer 1

x!/2!(x-2)! = 21
X(x-1)(x-2)!/2(x-2)! = 21
X^2 - x = 42
X^2 - x- 42 = 0

Delta= 169

X= 1 +- 13 / 2
x'= 7
x''= -6

S= (-6,7)