If f(x)=−2x+5, then one can evaluate f(−3x) by substituting −3x for every instance of x. This yields f(−3x)=−2(−3x)+5, which simplifies to 6x+5. Choices A, C, and D are incorrect and may be the result of miscalculations in the substitution or of misunderstandings of how to evaluate f(−3x).