Question 1197248
#2:


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Bx+4y=16
4x-7y=26
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7*E1 and 4*E2


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7Bx+28y=112
16x-28y=104
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ADD corresponding terms.

{{{7Bx+16x=216}}}

{{{(7B+16)x=216}}}

{{{highlight(x=216/(7B+16))}}}



Back to the original system,
4*E1 and B*E2

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4Bx+16y=64
4Bx-7By=26B
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E2-E1

{{{-7By-16y=26B-64}}}
{{{-(7B+16)y=26B-64}}}
{{{y=-(26B-64)/(7B+16)}}}

{{{highlight(y=(64-26B)/(7B+16))}}}