Question

Please Help!!!!!!!

Solve each system using elimination. Tell whether each system has no solution, infinitely many solutions, or one solution.
1. x+2y=23
5x+10y=55
2. 5x+4y=-83
3x-3y=-12
3. 4x+y=21
-2x+6y=9

Answer 1

are you familiar with elimination system?

Answer 2

Yes I just have a lot of work to do and don't have time to go over it step-by-step. My deadline is tonight.

Answer 3

I don't think I could use elimination on these.. I can't find a common number... subsitution would be better

Answer 4

you can @UsukiDoll

Answer 5

well ok maybe but isn't that for elimination you need like a 5x on the first equation and -5x on the second... that's just an example btw

Answer 6

Well can any of you help me???????

Answer 7

x+2y = 23 --
5x+10y = 55
multiply the first equation by 5 then subtract it the 2nd equation, see what you get

5x+10y = 115
5x+10y = 55
now subtract them

Answer 8

40

Answer 9

no, subtract the like terms
5x+10y = 115
- 5x+10y = 55
--------------
0 + 0 = 60 --- so this would have no solution

Answer 10

Ok I get it...

Answer 11

both the variables cancels out when ever you are trying to eliminate them, which leaves them with no solution

Answer 12

for the second one, think of which variables you want to eliminate first
then find there common number
then either subtract of add depending on their sign

Answer 13

. 5x+4y=-83
3x-3y=-12
Eliminate 4y and 3y and 5x and 3x
I think...

Answer 14

you have
5x+4y=-83
3x-3y=-12
so lets say, you want to eliminate the x first
so you would find 5 and 3 common number

Answer 15

So what do u mean by common number?

Answer 16

5 and 3 had common number of 15
because if you multiply 5 and 3 you would get 15

Answer 17

Ohh yaaa...

Answer 18

so you would multiply
5x+4y=-83--- multiply by 3
3x-3y=-12--- multiply by 5

Answer 19

S0 4y and 3y common number is 12?

Answer 20

yes

Answer 21

So basically 5x+4y=-83 and 3x-3y=-12 has 1 solution?

Answer 22

I graphed it and got only 1 solution...

Answer 23

yeah, but dont you want to know how to solve it
5x+4y=-83--- multiply by 3
3x-3y=-12--- multiply by 5
so
15x+12y = -249
15x-15y = -60 --- subtract them
---------------
0 - 27y = -189 -- divide both sides by 27
y = -7

Answer 24

Yes I get that and now I need the 3rd one...

Answer 25

do the same thing we did for the 2nd one
first pick a variable to eliminate and then find their common number
then subtract or add the 2 equations depending on their signs

Answer 26

4x+y=21
-2x+6y=9
Like terms- x= -8 and for y it is just 6? as there i no value for y in the 1st equation

Answer 27

the coefficient for the first y is just 1

Answer 28

Ok so the y like term is 6?

Answer 29

So the like terms are -8 and 6?

Answer 30

it can be 4 and 6, because when you multiply 2 by 2, you would get 4, so you dont really need to do anything to the first equation to eliminate the x

Answer 31

Ok

Answer 32

so
4x+y=21
-2x+6y=9--- multiply by 2

4x+y=21
-4x+12y=18 now since the second 4 is negative, add them
-------------
0 +13y = 39 divide both by 13
y = 3

Answer 33

do the same process to find the x
eliminate the y then solve for x

Answer 34

I get it now....thx!

Answer 35

no prob

Answer 36

So is x 3?

Answer 37

no it should be
4x+3 = 21
4x = 18
x=4.5

Answer 38

Oh yes I messed up in the multiplying part :P I am just soo overwhelmed with the work I have...

Answer 39

So 1 solution right?

Answer 40

right

Answer 41

Ok thx!!