Week 9-Modelling and Solving Problems with Quadratic Functions

This week we learned three formula form

General Form : $y=ax^2+bx+c$

Standard Form(Vertex form:Ms.Burton’s Favorite): $y=a(x-p)^2 +q$

X point form(x intercept form):y=(x-x_1)(x-x_2)

Ex:the rectangular have the area is to be bounded by 120 m of fencing(determine max area)

so we can get two formula

2L+2W=120

L*W=mix

so we can use the first formula get this form

L+W=60

L=60-W

SO PUT THIS FORMULA INTO THE SECOND FORMULA

(60-W)*W=MIX

We can get

$-(w-30)^2 +900=MIX$

So the vertex is (30,900):the 30 m is the w , and the $900 m^2$ is the MIX area

so we can use the formula L=60-W ,to get the L=30

so it is a square .the special rectangular

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