Question 962793

{{{5x - 4y= -3}}}
{{{2x + 7y= 5}}}
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{{{5x - 4y= -3}}}.....both sides multiply by {{{2}}}
{{{2x + 7y= 5}}}.....both sides multiply by {{{5}}}
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{{{10x - 8y= -6}}}
{{{10x + 35y= 25}}}
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{{{10x - 8y-10x-35y= -6-25}}}

{{{-43y= -31}}}

{{{y= -31/-43}}}

{{{highlight(y= 31/43)}}}.....exact solution

{{{highlight(y= 0.72)}}}......approximate solution


now, use exact solution of {{{y}}} to find {{{x}}}

{{{2x + 7y= 5}}}

{{{2x + 7(31/43)= 5}}}

{{{2x + 217/43= 5}}}

{{{2x = 5-217/43}}}

{{{2x = 215/43-217/43}}}

{{{2x = -2/43}}}

{{{x = -cross(2)/(cross(2)*43)}}}

{{{highlight(x = -1/43)}}}.....exact solution

{{{highlight(x = -0.023)}}}......approximate solution