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Home Q & A Board Science-Related Homework Help Mathematics
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smilemslisa smilemslisa
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11 years ago
10x-9y=18
6y+2x=1
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wrote...
#1
11 years ago
10x -9y = 18
5(2x+6y) = 5(1)

10x-9y=18
10x+30y=5

(10x-9y)-(10x+30y) = 18-5
-9y-30y = 13
- 39 y = 13
y = -3

Sub y = -3 into 6y +2x = 1
6(-3) + 2x = 1
-18 +2x = 1
-18-1 = -2x
x = 19/2
x = 9.5

I hope i didnt make a mistake..
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rizkallah15rizkallah15
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#2
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11 years ago
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#3
11 years ago
First write them so x's are first in each

10x -9y = 18
2x  +6y = 1

multiply 2nd by 5 to make number of x's same

10x-9y=18
10x+30y = 5

subtract

-39y = 13
y = 13/-39 = -1/3

put value in 2nd
2x + 6(-1/3)=1
2x -2 =1
2x = 3, x=3/2

check using values in 1st equation
correct
wrote...
#4
11 years ago
10x-9y=18
-5(6y+2x)=1
so:
10x-9y=18
-10x-30y=-5
by addition of two equation:
-39y=13
so: y = - 1/3
thus substitute value of y:
10x-9(-1/3)=18
thus: x = 3/2
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