Which of the following functions is not defined when x = 0? -
sin-1 (c)
O f(c) sec (3)
O f(x) = sin
O f(x) = csc (2)
O f(x) cos? (2)

In a column proof the right column states your reasons

Cherie works in retail and her weekly salary includes commission for the amount she sells. the equation s=400+0.15c models the relation between her weekly salary, s, in dollars and the amount of her sales, c, in dollars. interpret the slope of the equation.

Which pair of expressions is equivalent? a 7(1–k)and7–k b 7(1–k)and1–7k c 7(1–k)and7–k d 7(1–k)and7–7k