Question

Two equations are given below:

a − 3b = 4
a = b − 2

What is the solution to the set of equations in the form (a, b)?

(−2, −2)
(−3, −1)
(−9, −7)
(−5, −3)

Answer 1

please help

Answer 2

can anyone help?

Answer 3

since you know what a is equal to plug its value into the first equation so that you have the first equation only in terms of b, then solve for b

Answer 4

@AliSurfCat ok?

Answer 5

I really dont know

Answer 6

what is a equal to? according to the second equation

Answer 7

thats the thing I dont know:(

Answer 8

if i show you this, z = 10, what is z equal to?

Answer 9

10

Answer 10

perfect, now if i show you this, a = b − 2, what is a equal to?

Answer 11

a equals 4

Answer 12

a equals b - 2

Answer 13

and be equals 6

Answer 14

no, a equals b - 2

Answer 15

okay

Answer 16

ok lets make sure you understand this, if i show you j = 5i +z - 2, what is j equal to?

Answer 17

5i +z - 2

Answer 18

perfect :)

Answer 19

ok back to your question, so we know a is equal to b - 2

Answer 20

since a is equal to b -2 can you please replace a in the first equation with b -2 since they equal the same thing

Answer 21

ok, b-2 − 3b = 4

Answer 22

perfect :)

Answer 23

now can you solve for b? with that equation b -2 -3b = 4

Answer 24

cna you help me on this one?

Answer 25

sure

Answer 26

to solve for b we need to find out what b equals, so we have an equation that has only numbers and the variable b, so we need to perform some arithmetic on the equation to get b by itself on one side of the equals sign

Answer 27

so lets start by only getting terms with a b in them on one side,

so if you have b - 2 - 3b = 4, what would be a good step to take so that there are only terms with b in them on the left side?

Answer 28

how can i get rid of the -2 on the left side?

Answer 29

ok

Answer 30

what happens if we add 2 on both sides of the equation, what do you get?

Answer 31

you get 6

Answer 32

i get 6 on the right hand side of the equals sign but what about on the left side?

Answer 33

b - 2 + 2 - 3b = 4 + 2

b - 2 + 2 - 3b = 6

Answer 34

hey I have a few minutes left to turn this in please help

Answer 35

i am helping, if you just want the answer, i cant do that

Answer 36

I dont but think it is A

Answer 37

good luck bud

Answer 38

ok well thanks

Answer 39

if you change your mind and want to keep working through it let me know

Answer 40

I do :)

Answer 41

ok so we added 2 to both sides to get this

b - 2 + 2 - 3b = 4 + 2

b - 2 + 2 - 3b = 6

can you simplify this and tell me what we get?

Answer 42

b-4-3b=6

Answer 43

close, but

-2 + 2 is not equal to -4

Answer 44

ohhh sorry got a little confused

Answer 45

ok so -2 + 2 = what?

Answer 46

it eaquals 0

Answer 47

perfect,

now we have

b + 0 - 3b=6

which equals

b - 3b = 6

Answer 48

can you simplify b - 3b = 6 by combining the b terms?

Answer 49

how do I do that

Answer 50

if i have 1b and i take away 3b's how many b's do i have?

Answer 51

do I just do 3b=6???

Answer 52

1b - 3b

Answer 53

--2b

Answer 54

correct

Answer 55

so we are almost done

we have

-2b = 6, now how can you get b by itself?

Answer 56

how can we get rid of the -2?

Answer 57

turn it into a 1

Answer 58

by adding 2 on both sides

Answer 59

by dividing both sides by -2

Answer 60

yes thats what I meant lol

Answer 61

-2/-2 = 1

so

(-2b)/-2 = 6/(-2)

1b = 6/(-2)

b = 6 / (-2)

Answer 62

so what is 6 / (-2),

6 divided by -2

Answer 63

-3

Answer 64

perfect, so b = -3, so now you know the answer, do you see an answer where the second number is -3?

(a, b)

(a, -3)

Answer 65

which one is it?

Answer 66

we can find a very easily also

looking at the second equation we have a = b - 2

so if i plug in b i get

a = -3 -2

Answer 67

so it is D?

Answer 68

correct :)

Answer 69

yay thanks so much

Answer 70

you're welcome, please do some practice on this stuff or your future classes in college will be very difficult, visit khan academy and get help on here and other sites also

Answer 71

I do

Answer 72

good :)

Answer 73

have a good day

Answer 74

you too

Answer 75

nice to see too much long conversation in such a simple question