f(x) = x + 8x + 15 (a) Express f in standard form. f(x) = (x+4)-1=0 (b) Find the vertex and x- and y-intercepts of f. (If an answer does not exist, ente vertex (x, y) = -4, -1 x-intercepts (x, y) = -5,0 (smaller x-value) (x, y) = -3,0 (larger x-value) y-intercept (x, y) = 0, 15 (c) Sketch a graph of f. 10 9 Clear All 8 7 6 4