Sketch the graph of the function y = x2 − 6x + 8
Step 2 Find the interceptsPut x = 0 into the equation.
y = 02 − 6 x 0 + 8y = 8The y-intercept is 8
0 = (x − 4)(x − 2)x = 4 or x = 2The x-intercepts are 4 and 2
Step 3 Axis of symmetry is always midway between the x-intercepts.
Average of x-intercepts= (2 + 4)÷ 2 = 3
Axis of symmetry is the line x = 3
Step 4 Find the coordinates of the vertex.
The vertex occurs at x = 3When x = 3y = (3 − 4)(3 − 2)y = -1The vertex is at the point (3, -1)
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