Question 719830

{{{-5x - 7y = -15}}}..eq.1
{{{x + 2y = 6}}}...eq.2
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start with {{{x + 2y = 6}}}...eq.2 and solve for {{{x}}}


{{{x= 6-2y}}}...eq.2a....substitute in eq.1


{{{-5(6-2y) - 7y = -15}}}..eq.1...solve for {{{y}}}


{{{-30+10y -7y = -15}}}

{{{3y = -15+30}}}

{{{3y = 15}}}

{{{y = 15/3}}}

{{{highlight(y = 5)}}}...go back to eq.2a, substitute {{{5}}} for {{{y}}} and solve for {{{x}}}

{{{x= 6-2*5}}}...eq.2a

{{{x= 6-10}}}

{{{highlight(x= -4)}}}