Question

Can someone help me with this question?
Solve the system.

-3x + 4y = -22
2x + 7y = 5
A)
(6, -1)
B)
(-1, 6)
C)
(-6, 1)
D)
(-1, -6)

Answer 1

multiply first equation by 2, what do you get?

Answer 2

where do I multiply the two on the first equation?

Answer 3

on both sides of the equation.
you have to multiply each term on both sides by 2

Answer 4

B

Answer 5

@FINYA
direct answers are against the rules

Answer 6

-6x+8y=-22?

Answer 7

yes exactly :)

Answer 8

in the same way, multiply second equation by 3

Answer 9

could you explain why you multiply by 2?

Answer 10

HMMMM sorry I'm russian and I do not know your rules)

Answer 11

i'll show you,
for now multiply 2nd equation by 3

Answer 12

6x+21y=5

Answer 13

oh sorry, i dint notice, you have forgotten to multiply the right side of the equations

Answer 14

you have to multiply both sides of the equation

Answer 15

-6x+8y=-44? and 6x+21y=15

Answer 16

yes!! :)

Answer 17

o_O
Just make this
2x+7y=5
2x=5-7y
x=(5-7y)/2
-3*((5-7y)/2)+4y=-22
continue and find y

Answer 18

the rule for equations is that you are allowed to anything to them, but you have to do them for BOTH sides. if you do that, the equation will continue to hold true.

Answer 19

but why are we multiplying them?

Answer 20

so your two equations are
-6x + 8y= -44
6x +21y = 15

Answer 21

now add them , what do you get?

Answer 22

29y=-29

Answer 23

haha! excellent

Answer 24

now can you solve and find 'y' ?

Answer 25

hint: divide both sides by 29

Answer 26

y=-1

Answer 27

Exactly !!

Answer 28

now how do I find x?

Answer 29

awesome, so you understand x and y are unknowns, and that you need to find them

Answer 30

2x+7y=5
yoy know that y = -1
so

Answer 31

just take any 1 of you equations
for example
2x + 7y = 5

Answer 32

yes, I also know the substitution method but I need to know the elimination method

Answer 33

then subtitute -1 for y?

Answer 34

lol, i have very little to teach you

Answer 35

absolutely correct

Answer 36

what do you get for x?

Answer 37

x=6

Answer 38

CONGRATULATION!

Answer 39

but im still confused on why u multiply by 2 and 3?

Answer 40

kx=kx => 6x=6x so you can reduce it
sorry for my bad english

Answer 41

no?

Answer 42

congrats indeed animecore

Answer 43

could you help me with one more question?

Answer 44

yes finya is correct.

why I did that is, if both the 'x' have the same number, when you add them, they conveniently cancel and leave only y.

Answer 45

we got 6x and -6x
when we add them, we get zero :)

Answer 46

oh ok

Answer 47

i have to go now, perhaps @FINYA will help. or you can tag me, and i'll have a look when i have time

Answer 48

ok thanks for your help

Answer 49

could you help me @FINYA ? its a simple question but I dont know where to start on it

Answer 50

I am going to english corses
So I have several minutes

Answer 51

ok