Question 228648
3x-y=7  Equation A
y=4x-11 or -4x+y=-11  Equation B


Step 1.  Add Equations A and B to eliminate the y-variable.


{{{3x-4x-y+y=7-11}}}


{{{-x=-4}}} or {{{x=4}}} after multiplying by -1 to both sides of the equation.


Step 2.  Substitute {{{x=4}}}, into equation A {{{3x-y=7}}}


{{{3*(4)-y=7}}}


Add y-7 to both sides of the equation  


{{{12-y+y-7=-7+y-7}}}


{{{5=y}}}


Check if {{{x=4}}} and {{{y=5}}} satisfies Equation B {{{-4x+y=-11}}}


{{{-4*(4)+5=-16+5=-11}}} which it does.


Step 3.  The solution is x=4 and y=-11.


I hope the above steps were helpful.


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Good luck in your studies!


Respectfully,
Dr J