Question

Which quadratic equation fits the data in the table? A. y = -x^2- x - 3 B. y = x^2 - x+3 C. y = x^2 -x - 3 D. y = x^2 +x +3

Answer 1

`"Answer B"`

Explanation:

`"First look at the value x=0 to see the constant."`
`"The constant is 3, so it can only be B or D."`
`"Then look at another value to determine if it is -x or +x."`
`"We see it must be -x. => Answer B."`
`"No need to do regression analysis here, it is only simple algebra."`

Answer 2

`B"`

Explanation:

`"essentially substitute selected values of x into the given"`
`"equations and check the value of y"`

`"choosing check values of "`

`"say "x=-5,x=0" and "x=6`

`"working through the equations systematically we find"`

`B`

`x=-5to`

`y=(-5)^2-(-5)+3=25+5+3larrcolor(blue)"checks"`

`x=0to`

`y=0-0+3=3larrcolor(blue)"checks"`

`x=6to`

`y=6^2-6+3=36-6+3=33larrcolor(blue)"checks"`