Question 651677

i know how to do algebra problems using the addition method, however i can not get the answer to one question

the problem is 1/4x -1/6y=-1
             
              -1/18x +1/15y=2



x= 36     y= ?     i can not even find x. someone gave me the answercan you show me how to work this out.    thank you


{{{(1/4)x - (1/6)y = - 1}}}
3x – 2y = - 12 ----- Multiplying by LCD, 12 ----- eq (i) 


{{{- (1/18)x + (1/15)y = 2 }}}
- 5x + 6y = 180 ------ Multiplying by LCD, 90 ------- eq (ii)
9x – 6y = - 36 ------ Multiplying eq (i) by 3 ---- eq (iii)
4x = 144 ------ Adding eqs (iii) & (ii)


x = {{{144/4}}}, or {{{highlight_green(36)}}}


3(36) – 2y = - 12 ------ Substituting 36 for x in eq (i)
108 – 2y = - 12 
– 2y = - 12 – 108 
– 2y = - 120


y = {{{(- 120)/- 2}}}, or {{{highlight_green(60)}}}


You can do the check!!


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