Question

hi can someone give me some elimatnition and substitution method to solve

Answer 1

i have a test tommorow on this so could u help me preper for it

Answer 2

please

Answer 3

sure try this:

2x+3y=16
-4x+y=10

Answer 4

and this:

A red ticket costs 1 dollar. A blue ticket costs 3 dollars. Tom spent a total of 30 dollars on tickets and bought 16 total tickets. How many blue tickets and how many red tickets did he buy?

Answer 5

is this the kind of problem you are talking about?

Answer 6

yes thanks

Answer 7

the first one is x=-1, y=6

Answer 8

is that right

Answer 9

yep that's right

Answer 10

did you try the word prob?

Answer 11

no i am

Answer 12

can u help me on that because i am so bad at word promblem

Answer 13

sure. we know the price of a blue ticket and red ticket, and let's use b and r to denote how many blue tickets and red tickets are bought. Can you translate the problem into an equation for total money spent using the variables b and r first?

Answer 14

write an expression for how much you spend if you buy b blue tickets and r red tickets and set that equal to the given total 30 dollars

Answer 15

this is not goin to be on my test but it is just questions can u give me those

Answer 16

please

Answer 17

im not sure what you mean, you want me to give you the solution to the problem I wrote?

Answer 18

or you want a different one?

Answer 19

a difefernt one like the first one

Answer 20

ok I'll set up the word problem for you and you can solve that

3b+r=30
b+r=14

Answer 21

ok

Answer 22

ok i got how u set it up

Answer 23

but shouldnt the 14 be 16

Answer 24

3b+r=30
b+r=14

Answer 25

shuldnt the 14be a 16

Answer 26

how did u get 14

Answer 27

im just a little confused

Answer 28

ok i got b=8, r-6

Answer 29

is it right

Answer 30

woops i meant to say 14 total tickets. b=8 r=6 is right for 14 total tickets

Answer 31

good you did it correctly and found a mistake haha

Answer 32

ok

Answer 33

what else is on the test?

Answer 34

can u give me another promblem on this so im okay on this

Answer 35

not a word promblem

Answer 36

word problem or just a system of equations?

Answer 37

ok let me write one

Answer 38

do you ever do more than 2 equations?

Answer 39

3 equations 3 variables>?

Answer 40

i do u can give me that if u want

Answer 41

k lets do one of those

Answer 42

ok

Answer 43

2x-z+3y-18=0
4z+5x-2y=-18
-6y+z+3x+52=0

Answer 44

that should be a little more difficult

Answer 45

u it is can u go over it step by step with me please

Answer 46

so i understand

Answer 47

iv tried this before and i have always had trouble on this

Answer 48

sure start by lining up the variables:
2x+3y-z=18
5x-2y+4z=-18
3x-6y+z=-52

Answer 49

now lets eliminate z first by multiplying the top equation by 2 and the bottom by -2

4x+6y-2z=18
5x-2y+4z=-18
-6x+12y-2z=104

Answer 50

is there an easier way to solve this do u think

Answer 51

add those three equations.

Answer 52

this is the typical way to do it by hand

Answer 53

ok

Answer 54

is this 18 suppsosed to be 36 in the first equation, because we mulitied each one by two

Answer 55

yep sorry

Answer 56

k

Answer 57

when you add them you get one equation with x and y. so you can solve for one in terms of the other. then you plug into two of the original equations and you have a system of 2 equations and two unknowns

Answer 58

can u help me furthere im stuck

Answer 59

ok adding all the equations you get 3x+16y=122

x=(122-16y)/3

Answer 60

okk i got it

Answer 61

thanks

Answer 62

now you can plug into two of the equations and get numbers for x,y,z

Answer 63

i got it

Answer 64

can u help me with this one 5/x+5-7/x-5=12/x^2-25

Answer 65

i ma getting 1 as my answere

Answer 66

x^2-25=(x+5)(x-5)

5*(x-5)/{(x-5)(x+5)}-7(x+5)/{(x-5)(x+5)}=12/{(x-5)(x+5)}

5x-25-7x-35=12
-2x=72
x=-36

I read the equation as:
\[\frac{5}{x+5}-\frac{7}{x-5}=\frac{12}{x^2-25}\]

Answer 67

ok i got it it is -36

Answer 68

i found my mistake

Answer 69

good :)

Answer 70

can u give me one substution mehtod promblem

Answer 71

please

Answer 72

ok. Mary is 11 years older than her little sister. In 9 years she will be twice as old as her little sister. How old are mary and her sister?

Answer 73

is this one ok?

Answer 74

yes hod on i will be back

Answer 75

i am going to take a showere and i will be back

Answer 76

i am going to take a showere and i will be back

Answer 77

what time are u at right now

Answer 78

4:53

Answer 79

i may not be here so the solution is Mary-13, sister-2. See if you can get that using substitution

Answer 80

ok

Answer 81

thamk s

Answer 82

i gave u a medall did u get it

Answer 83

yep i did, thanks :) good luck on the test

Answer 84

ok thanks