Today we talked about the generic formulae for solving a quadratic equation of ax^2 + bx + c = 0

x= (-b +/- sqrt(b^2-4ac))/(2a)

We did exercise of using the formulae to solve some quadratic equations.

We further talked about the real life example of throwing an object, with the following mode:

h = -16t^2 +vt + s

where s is the initial height in feet, v is the initial speed (ft/s), t is the time, and h is th height at t time. When throwing an object upward, v has a positive value; when throwing the object downward, v has a negative value.

The terms inside the radical in the formulae is called discriminant. We talked about the application of the discriminant, and use it to determine how mnay solutions to get.

We further related the formulae to the graphing, and the relationship between the solutions and the x-intercepts.

For homework, visit the following link:

http://blog.newtonchineseschool.org/wangweidong/files/2011/12/Math7_Fall_HW_L11.pdf