Graph Modelling (Completing the square)

What are the 3 options to answer question

• Look at the marks

• Quadratic equation = 0

• ax2 +ax + c = 0

• y-intercept (last number “c”) is the answer

• Completing the square

How many marks for y intercept is answer

1-2 mark

How do I know when to use quadratic = 0

• If the question asks

• MAX/MIN

• Values

• 4-5 marks

• If unsolvable use quadratic equation

How do I know when to use completing square

• 4-5 mark

What does y=ax2+b indicate

Minimum Value

What does y=-ax2+ b mean

Max value

What is the rule for completing the square equations

• When y=a-b(x-c)2 or y= a(x-p)2 +c

• Look inside or outside bracket

What do I do when question asks for x value, Input, price, time

• Asking for x value,

• Input, price, time

• When do I look for inside the bracket of y=a(x-p)2 + c

• INSIDE the bracket (p-20)2 = 0

• p = 20

Where do I look when question asks or MAX/MIN

• Look OUTSIDE the brackets

• Look at the numbers

• then formulate answer

What are the options with IV and DV

• Set IV → 0

• Which “variable = 0” means

• What DV equals at that point

• y = mx2 + b = initial (value)