6.8 Solving Equations by Factoring
Zero Product Property Rule if (a)(b) = 0, then a = 0 or b = 0 Zero Product Property Rule if (a)(b) = 0, then a = 0 or b = 0. if a = 0 or b = 0, then (a)(b) = 0.
the quest for “X” X
Solving for X If the equation is already factored and set equal to 0 then: set each factor equal to 0 solve
What values of “x” make this equation true? (x + 1)(x – 7) = 0
What values of “x” make this equation true? x(2x – 9) = 0
What values of “x” make this equation true? (x + 3)(x – 4) = 0
What values of “x” make this equation true? (x - 7)(x – 3) = 0
What values of “y” make this equation true? y(3y – 17) = 0
If the equation is not already factored then you need to: Solving for X If the equation is not already factored then you need to: set it =0 factor it set each of its factors =0, solve for x
Solve for “y”: y2 + 5y = -6 Add 6 to get “0” on one side Factor Let each factor = zero
Solve for “y”: y2 – 8y = -16 Add 16 to get “0” on one side Factor
x2 – x – 6 = 0 x = 3 or (-2)
m2 – m = 56 m = 8 or (-7)
k2 – 3k = 28 m = 7 or (-4)
“root” For a polynomial containing a variable, any value of the variable that makes the value of the polynomial = zero is called a “root” of the polynomial. Find the roots of x2 – 5x = 0
Find the roots of 25x2 – 16
Assignment Page 289 (2-68) even