a is the coefficient of the x^2 term.
b is the coefficient of the x term.
c is the constant term.
you find the values of a,b,c and plug them into the formula.
an example:
x^2 - 4x + 3 = 0
a = 1
b = -4
c = 3
the quadratic formula is:
x =
if b is equal to -4, then -b is equal to 4.
if a is equal to 1, then 2a is equal to 2.
if b is equal to -4, then b^2 is equal to 16.
if a is equal to 1 and c is equal to 3, then 4ac is equal to 4*1*3 = 12
you plug these values into your quadratic formula to get:
x =
you simplify this equation to get:
x =
you simplify this equation further to get:
x =
this becomes x = 6/2 = 3, or x = 2/2 = 1
x is either equal to 1 or x is equal to 3.
a graph of the equation y = x^2 - 4x + 3 looks like this:
you can see from the graph that y crosses he x-axis when x = 1 and when x = 3.
x = 1 and x = 3 are the roots of your equation.
using the quadratic formula is simply a matter of plugging in the right values for a,b,c in the equation and then solving it.
