Question 123342
# 4


If we have the solution (-3,4) , this means that {{{x=-3}}} and {{{y=4}}}


Let's solve for b:


{{{5x+7y=b}}}  Start with the first equation


{{{5(-3)+7(4)=b}}}  Plug in {{{x=-3}}} and {{{y=4}}}



{{{-15+28=b}}} Multiply 5 and -3 to get -15. Multiply 7 and 4 to get 28. 


{{{b=13}}} Add -15 to 28 to get 13



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So our first answer is {{{b=13}}} 

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Now let's solve for m:


{{{mx+y=22}}} Start with the second equation


{{{m(-3)+(4)=22}}} Plug in {{{x=-3}}} and {{{y=4}}}


{{{-3m+4=22}}} Multiply m and -3 to get {{{-3m}}}. 


{{{-3m=18}}} Subtract 4 from both sides


{{{m=-6}}} Divide both sides by -3



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So our second answer is {{{m=-6}}} 

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Summary:


So our answers are:

 {{{b=13}}} and {{{m=-6}}}