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Mathematics 14 Online
OpenStudy (graceland00):

MEDAL FOR RIGHT ANSWER!!!

OpenStudy (graceland00):

A function is shown in the table. x g(x) −3 17 −1 −3 0 −4 2 13 Which of the following is a truestatement for this function? (5 points) The function is increasing from x = −3 to x = −1. The function is increasing from x = −1 to x = 0. The function is decreasing from x = 0 to x = 2. The function is decreasing from x = −3 to x = −1.

OpenStudy (thereisnousername):

you can find the minimum value of a quadratic function by using the formula -b/2a if we assume that the equation is given in the form y=ax^2 + bx +c then, try to plot the values of the second function roughly on a graph paper or even a simple paper will do good with some estimation and then, you can get the answer

OpenStudy (thereisnousername):

assume that we have a quadratic equation of the form y=ax^2 + bx + c now, compare the equation y=ax^2 + bx + c (we call it the standard equation) to the given equation, i.e. f(x) = 3x2 + 6x + 7 so we get a=3, b=6, c=7 now put the values of a abd b in the formula that i have specified in the above post

OpenStudy (graceland00):

ok so the answer would be...?

jimthompson5910 (jim_thompson5910):

@Graceland00 are you able to find the slope of the line through any two points? Are you familiar with the slope formula?

OpenStudy (graceland00):

y=mx+b?

jimthompson5910 (jim_thompson5910):

I'm referring to this slope formula \[\Large m = \frac{y_2-y_1}{x_2-x_1}\]

OpenStudy (graceland00):

ohhh

jimthompson5910 (jim_thompson5910):

does it look familiar?

OpenStudy (graceland00):

yes

jimthompson5910 (jim_thompson5910):

focus on the two rows −3 17 −1 −3 so we have the two points (-3,17) and (-1,-3) what is the slope of the line through the two points (-3,17) and (-1,-3) ?

OpenStudy (graceland00):

I'm not very sure

jimthompson5910 (jim_thompson5910):

Let (x1,y1) = (-3,17) and (x2,y2) = (-1,-3) Plug these coordinates into the slope formula to get \[\Large m = \frac{y_2-y_1}{x_2-x_1}\] \[\Large m = \frac{-3-17}{-1-(-3)}\] \[\Large m = \frac{-3-17}{-1+3}\] \[\Large m = ???\] I'll let you simplify

OpenStudy (graceland00):

m=-17/2

jimthompson5910 (jim_thompson5910):

-3-17 is equal to what?

OpenStudy (graceland00):

-17

OpenStudy (graceland00):

-20

OpenStudy (graceland00):

sorry

jimthompson5910 (jim_thompson5910):

that's fine

jimthompson5910 (jim_thompson5910):

yes, -3-17 is equal to -20

jimthompson5910 (jim_thompson5910):

so \[\Large m = \frac{-3-17}{-1+3}\] \[\Large m = \frac{-20}{2}\] \[\Large m = -10\] slope = -10

OpenStudy (graceland00):

ok

OpenStudy (graceland00):

what next

jimthompson5910 (jim_thompson5910):

The slope from x = -3 to x = -1 is \(\large -10\) Since the slope is negative, this means the function is \(\large \text{Decreasing}\) from x = -3 to x = -1

OpenStudy (graceland00):

thank you!

jimthompson5910 (jim_thompson5910):

choice A says `The function is increasing from x = −3 to x = −1.` which is the opposite of what I just posted. So choice A is incorrect

jimthompson5910 (jim_thompson5910):

you'll go through the other sub-intervals and see which are increasing or decreasing. Compare what you get to the answer choices

OpenStudy (graceland00):

ok thanks of the help! i really appreciate it

jimthompson5910 (jim_thompson5910):

no problem

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