y can be eliminated from the system of equations: 4x + 7y = 12 (3) x + y = 4 by adding the equations after multiplying the second equation by: a) -4 b) 4 c) -7 d) 7 e) none of these

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inchu420 inchu420 · Answer 1 · 2020-03-18T05:20:01+01:00

Answer:

Therefore,

The Correct option is C) -7

Step-by-step explanation:

Given:

[tex]4x+7y=12[/tex] ...........Equation ( 1 )

[tex]3x+y=4[/tex] ...........Equation ( 2 )

To Find:

The Correct option for Eliminating "y"

Solution:

So to Eliminate "y" we need to add the equations after multiplying the second equation by " - 7 " (i.e option C) -7 )

So Equation ( 2 ) become

[tex]-7\times (3x+y)=-7\times 4[/tex]

Applying Distributive Property we get

[tex]-21x-7y=-28[/tex]

Now by adding +7y and -7y will get eliminate and we get

[tex]-17x=-16\\\\17x=16[/tex]

Therefore,

The Correct option is C) -7