Open Middle®
Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to create a quadratic in factored form with the lowest minimum.
Hint
How does the location of the vertex change when the x-intercepts are farther apart?
Answer
y = 8(x-1)(x-9)
Source: Ryan Kimes
y=8(x-1)(x-9) has a minimum value of 72 as that is the y-coordinate of the turning point? Surely y=2(x-1)(x-3) has a minimum value of 6 so would be the lowest minimum you could have?
Mins are -128 and -2 for the two equations you gave.