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Can someone please help me with my math homework ?

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Which value of x satisfies both -9x + 4y = 8 and -3x − y = 4 ?

a) -1/7
b) -7/9
c) -4/7
d) -9
e) -4/3

please help !
asked May 24, 2014 in ALGEBRA 1 by anonymous

1 Answer

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The equations are -9x + 4y = 8 and - 3x - y = 4 .

Now solve the equation (2) : - 3x - y = 4 for y .

-3x - y = 4

- y  = 4 + 3x

y = - 4 - 3x

Substitute the y value in equation (1) : -9x  + 4y  = 8.

- 9x + 4(- 4 - 3x ) = 8

- 9x - 16 - 12x  = 8

-21 - 16 = 8

-21x = 8+16

- 21x  = 24

= 24/-21

= -8/7

So the value is -8/7.

Thus there are no one value of x  in the options are not satisifies the both equations.

answered May 24, 2014 by david Expert

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