Question 116332

solve:
{{{5x + 2y = 28}}}....(1).........multiply by {{{2}}}
{{{3x -4y = 48}}}......(2)..
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{{{10x + 4y = 56}}}..........add (1) and (2) 
+{{{3x - 4y = 48}}}
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{{{10x + 3x + 4y -4y = 56 + 48}}}

{{{13x = 104}}}

{{{x = 104/13}}}

{{{ x = 8}}}

now eather from (1) or (2) find {{{y}}}

{{{10x + 4y = 56}}}..........(1)........move {{{10x}}} to the right

{{{ 4y = 56 - 10x}}}..........plug in {{{x}}}

{{{ 4y = 56 - 10*8}}}..........

{{{ 4y = 56 - 80}}}..........

{{{ 4y =  - 24}}}..........divide by {{{4}}}

{{{ y = - 24/4}}}..........

{{{ y = - 6}}}.......................solution

check:

{{{ x = 8}}}

{{{ y = - 6}}}

{{{5x + 2y = 28}}}....(1).........plug in {{{x}}} and {{{y}}}

{{{5+8 + 2(-6) = 28}}}

{{{40 - 12 = 28}}}
{{{28 = 28}}}


{{{3*8 -4(-6) = 48}}}......(2)..

{{{24 + 24 = 48}}}
{{{48 = 48}}}