Y = X2 - 8X + 12
set to 0
X2- 8X + 12 = 0
X2 - 8X = - 12
halve the coefficient of the linear term, ( - 8 ), square it and add it to both sides
X2 - 8X + 16 = - 12 + 16
factor on the left and gather term on the right
(X - 4)2 = 4
(X - 4)2 - 4 = 0
================vertex form
(4, - 4)
=======vertex
This can be done at least 2 ways.Soln 1: The saying: IS over OF equals PERCENT over 100, tells how to set up a proportion to solve.5/28 = x/100 ... cross multiply and solve for x28x = 500x = 17.86%Soln 2: Translate the word problem into an equation. IS means equals, OF means to multiply.x (28) = 5 solve, get a decimal answer and convert it to a percent.x = 5/28 = 0.1786 = 17.86%Pick which method you like best to use.