Question

Need help I will give medal

Answer 1

well the y- intercept is given (0, -4.5)

so that means you choices are the 1st or 3rd equations...

so substitute -2 into both equations and see which gives y = -23.5

then when you have 1 equation just check against the 3rd point

Answer 2

ok hold on

Answer 3

I put 2 in for x and still didnt get -23.5

Answer 4

which equation did you use..?

Answer 5

1 and 3

Answer 6

get out of here

Answer 7

hello

Answer 8

well in equation 1

\[-2.5 \times (-2)^2 + 4.5 \times (-2) - 4.5 = ?\]

Answer 9

sorry -10+-9-4.5

Answer 10

so is that equal to the y value you need..?

Answer 11

-24.5

Answer 12

its not -23.5 if that is what you are asking

Answer 13

you may want to check that -19 - 4.5 = -23.5

u

Answer 14

oops missed that

Answer 15

so its the first one

Answer 16

well you may like the check with the 3rd point... just to make sure

Answer 17

ok i will hold on

Answer 18

for the second one i got -4.5

Answer 19

I think you need to check your calculations

\[-2.5\times (4)^2 + 4.5 \times 4 - 4.5 = ?\]

Answer 20

i put in a -2

Answer 21

I'm using the 3rd point on the 1st equation...

Answer 22

but its -26.5

Answer 23

Isn't that what you want, for the 3rd point in the 1st equation...

Answer 24

i just want to know how to do this

Answer 25

the 3rd point x = 4

-2.5 * 4^2 = -40
4.5 * 4 = 18
- 4.5
----------
-26.5

so the 1st equation is true for the 3 points... I wouldn't go any further

Answer 26

ok... so do you understand that the y- intercept for the points given is

(0, -4.5)..?

Answer 27

ohhhh ok i get what your saying

Answer 28

so substitute x = 0 into the equations and the only ones that give y = -4.5 are the 1st and 3rd

so next use the point x = -2 y = -23.5

substitute x = -2 and see if you get y = -23.5

this happens in the 1st equation, the 3rd equation gives y = -17.5 I think...

so lastly use the 3rd point to check the 1st equation is the answer...

the point (4, -26.5) substitute x = 4 and see if you get -26.5

that's a simple process that uses elimination...using some observation and arithmetic

Answer 29

ok thx