Question 94042
Question:


I am having trouble with solving by substitution. Please help.

5x-2y=-5
y-5x=3


Answer

5x - 2y = -5 ----------------(1)


y - 5x = 3 ------------------(2)


(2) ==>  y = 3 + 5x



Substitute this value of y in the first equation.



  (1) ==> 5x - 5( 3 + 5x ) = -5



==> 5x - 5*3 -5*5x = -5



==> 5x - 15 - 25x = -5




==> 5x - 25x - 15 = -5



==> -20x - 15 = -5



Add 15 on both sides....




==> -5x - 15 + 15  = -5 + 15



==> -10x = 10


Divide both sides by -10



==> {{{ -10x/-10 = 10/10}}}



==> x = 1



==> y = 3 + 5x = 3 + 5*1  = 3 + 5 = 8



So the  solution is, {{{ x = 1 }}} and {{{ y = 8 }}}




Hope you found the explanation useful.



Regards.


Praseena.