How do you graph #y=x^2-2x-3#?

1 Answer
Aug 1, 2015

Find and plot: the vertex, the #x# intercepts, the #y# intercept (and any other test values for #x# you like); then connect the dots.

Explanation:

#y=x^2-2x-3 =(x-3)(x+1)#

#y# intercept #= -3##color(white)("XXXX")# (found by setting #x=0#)
#x# intercepts #=3# and #=-1##color(white)("XXXX")#(from the factors)

vertex: #(x,y) = (1,-4)##color(white)("XXXX")#(#x# by completing the square, #y# by substitution)
graph{x^2-2x-3 [-5.3, 7.19, -4.805, 1.435]}