Solve by elimination method:
9x-9y=36
7y-3x=-14
Another problem:
0.3x-0.2y=4
0.4x+0.5y=1

- anonymous

Solve by elimination method:
9x-9y=36
7y-3x=-14
Another problem:
0.3x-0.2y=4
0.4x+0.5y=1

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- anonymous

Hello i will help you today

- anonymous

thanks

- anonymous

.3x - .2y = 4 -->(1)
.4x + .5y = 1 -->(2)
(1)x5 you get 1.5x - y = 20
(2)x2 you get .8x + y = 2
Add up these two, you get 2.3x = 22
x = 220/23
Substitute x back into any equation, you get y = -130/23
and
5x +3y = -11 -- (1)
7x - 2y =19 -- (2)
(1)x2 you get 10x + 6y = -22
(2)x3 you get 21x - 6y = 57
Add the two, you get 31x = 35
So x = 35/31
Substitute x back into any equation, you get y = 172/31
and
9x - 9y =36 -- (1)
7y - 3x = -14 -- (2)
(2)x3 you get -9x + 21y = -42
Add this to (1), you get 12y = -6, so y = -1/2
Substitute y back into any equation, you get x = 7/2

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## More answers

- anonymous

tell me if that helps at all

- anonymous

the one problem i think you wrote wrong it was supposed to be 5x+2y=-7
7x-3y=11

- anonymous

ok i am srry hold on

- anonymous

okay

- anonymous

wait nevermind i wrote it wrong

- anonymous

5x+2y=-13
7x-3y=17

- anonymous

ok here we go
9x-9y=36 => x - y = 4 => x = 4+y
7y-3x=-14 => 7y - 3(4+y) = -14
7y - 12 - 3y = -14
4y = -2
y = -1/2
x = 4-1/2 = 7/2
(x,y) = (7/2, -1/2)

- anonymous

would you mind helping me on a few more

- anonymous

no i would love to

- anonymous

5x+2y=-13
7x-3y=17
0.05x+0.25=11
0.15x+0.05y=12

- anonymous

Substitution method:
7m+n=46
m-3n=16

- anonymous

Im really having trouble with the substitution one

- anonymous

ok

- anonymous

umm i cant to seem to get this won hold on and i am going to have some won help if that is ok with you

- anonymous

well what would the elimination problems be i sent you

- anonymous

ok is this it tight here
Start by multiplying the first equation by 2, and the second by 3:
10x + 6y = -22
21x - 6y = 39
Now add the two together, you y's cancel out , "eliminating" it.
21x = 17
x = 17/21
5x + 3y = -11
5(17/21) + 3y = -11
85/21 + 3y = -11
85 + 63y = -231
63y = -146
y = -146 / 63

- anonymous

okay thanks how about 0.05x+0.25y=11
0.15x+0.05y=12

- anonymous

ok here we go
5x + 25 y = 1100
15 x + 5 y = 1200
- 15x - 75y = - 3300
15x + 5y = 1200-----------ADD
- 70 y = - 2100
y = 30
5x + 750 = 1100
5x = 350
x = 70
x = 70 , y = 30

- anonymous

wow thanks your like a lifesaver haha

- anonymous

np i love to help

- anonymous

5x+5y=-11
7x-3y=17

- anonymous

this is done by elimination

- anonymous

i am on it

- anonymous

thanks!!!

- anonymous

5x+5y=-11 multiply by 2 ==> 10x + 10y = -22
7x-2y=17 multiply by 5 ===> 35x - 10y = 85
Add the two equations:
10x + 35x = -22+85
45x = 63
x = 63/45 = 7/5
substitute into original equation:
5(7/5) + 5y = -11
5y = -18
y = -18/5
Solution set: (x,y) = (7/5, -18/5)
ok do this help

- anonymous

it told me i was wrong

- anonymous

ummm that is weird

- anonymous

what r ypu working on so i know i might know why

- anonymous

its a math program and I have to enter the answers in and it lets me know if im wrong or not then submits it to my teacheer part of my homeschool

- anonymous

ok i do home schooling to i think i know what programe you talking about

- anonymous

okay

- anonymous

umm that i weird i woundr were we went wrong

- anonymous

i dunno im trying to figure it out too

- anonymous

Ill rewrite the problem

- anonymous

5x+5y=-11
7x-3y=17

- anonymous

ok

- anonymous

ok i think i got it
Let's just multiply everything by 100 to eliminate the decimals.
5x + 25y = 1100
15x + 5y = 1200
Multiply the first equation by 3
15x + 75y = 3300
15x + 5y = 1200
Subtract the second equation from the first
70y = 2100
7y = 210
y = 30
15x + 5(30) = 1200
15x + 150 = 1200
15x = 1200 -150
15x = 1050
x = 1050/15 = 70
Let's check in the original equations.
0.05(70) + 0.25(30) = 3.50 + 7.50 = 11 check.
0.15(70) + 0.05(30) = 10.50 + 1.50 = 12 check.
8 months ago Report Abuse

- anonymous

srry about the 8 month ago i did that srry

- anonymous

its okay

- anonymous

i was working on something els and it got out up there

- anonymous

did you see the word problem i posted could you help me with that

- anonymous

did you ever figure out that one problem for me

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