Question

The company discovered that it costs $28 to produce 2 camera cases, $50 to produce 4 camera cases, and $140 to produce 10 camera cases. Using the quadratic function, find the cost of producing 12 cameras.

Answer 1

P = ax^2+bx+c, P is total production cost, x is number of cases. solve for a,b,c using the three values you are given,

Answer 2

so, 28 = 4a+2b+c
50 = 16a+4b+c
140 = 100a+10b+c

Answer 3

solve for a,b,c

Answer 4

how do i do that?

Answer 5

do you know how to do matrices?

Answer 6

no

Answer 7

okay
28 = 4a+2b+c ---------------------------------------->Eqaution 1
50 = 16a+4b+c ---------------------------------------> Eqn 2
140 = 100a+10b+c----------------------------------> eqn 3

do eqn 3 - eqn 1
and do eqn 2 - eqn 1
and post what you got here

Answer 8

still don't know how to figure it out

Answer 9

Can you subtract equation 1 from equation 2 and post it here?

Answer 10

38=12a+2b

Answer 11

how did you get 38?

Answer 12

32*

Answer 13

i mean 22*

Answer 14

ok so repost the correct equation again

Answer 15

22=12a+2b

Answer 16

okay good. Now, the same way, subtract equation 1 from equation 3

Answer 17

112=96a+8b

Answer 18

okay. Now, can you solve the set of equations
12a + 2b = 22
96a + 8b = 112
?

Answer 19

can you help me with it.

Answer 20

okay, have you learned how to solve two equations for two unknown variables in school?

Answer 21

not that i can remember.

Answer 22

you haven't done basic algebra in school yet?

Answer 23

alright anyway,
12a + 2b = 22 ------------>eqnA
96a + 8b = 112----------->eqnB

Answer 24

do you know substitution to solve for a and b?

Answer 25

okay just do 4 times eqn A and post it here.

Answer 26

what do you mean

Answer 27

If you multiply both sides of equation A by 4, what do you get?

Answer 28

48a+2b=88

Answer 29

try again

Answer 30

that's multiplying both sides by 4.

Answer 31

so 2b*4 = 2b?

Answer 32

usually when i've done that, i've never done it to all. be more specific.

Answer 33

48a+8b=88

Answer 34

if a =4, then 4a =16
so we multiply both sides by 4.
so if a+b = 4
then 4(a+b) =16

Answer 35

okay good,
so 48a + 8b = 88--------------->eqn. C

Do you notice what we did there? we multiplied equation B by 4 so that both equation A and equation C have the term 8B in them. So now subtract equation C from equation A.

Answer 36

i'm still completely confused

Answer 37

what are you confused about?

Answer 38

OK join me
http://www.dabbleboard.com/draw?b=Guest654407&i=0&c=ce1b368e8fb4c87408d1e26d13c93f5bf92f9032

will explain in detail there

Answer 39

okay i'm on there