Use the definition of continuity and the properties of limits to show that the function is continuous at the given number a. F(x ) = (x+ 3x4), a=-1 lim f(x) = lim x - -1 x--1 11 lim x- -1 by the power law 11 lim (x) + lim x- -1 x--1 by the sum law 5 11 lim (x) + lim ( x 4 ) ) x--1 by the multiple constant law 11 by the direct substitution property Find f(-1). f( -1) = Thus, by the definition of continuity, fis continuous at a = -1