solve (x - 5)(x - 10) = -4
(x - 5)(x - 10) = -4
x^2 -5x -10x + 50 = -4
x^2 - 15x + 54 = 0
-b ± √(b² - 4*a*c)
x = ------------------------------
2a
-(-15) ± √((-15)² - 4*1*54)
x = ------------------------------
2(1)
15 ± √(225 - 216)
x = ------------------------------
2
15 ± √(9)
x = --------------
2
15 ± 3
x = ---------
2
18
x = ----
2
and
12
x = ----
2
x = 9 and x = 6
The graph of this equation crosses the x-axis
at (6,0) and (9,0)