Question 1008442

Solve the following system of equations 

1/3x -1/4y =-6

2x - 1/5y =2/5
<pre>{{{(1/3)x - (1/4)y = - 6}}} 
{{{x/3 - y/4 = - 6}}}
4x - 3y = - 72 -------- Multiplying by LCD, 12 ------ eq (i)

{{{2x - (1/5)y = 2/5}}} 
{{{2x - y/5 = 2/5}}}
10x - y = 2 --------- Multiplying by LCD, 5 ---------- eq (ii)
- 30x + 3y = - 6 ---- Multiplying eq (ii) by - 3 ----- eq (iii)
- 26x = - 78 -------- Adding eqs (iii) & (i)
x = {{{(- 78)/(- 26)}}}, or {{{highlight_green(3)}}}

4(3) - 3y = - 72 ------ Substituting 3 for x in eq (i)
12 - 3y = - 72
- 3y = - 72 - 12
- 3y = - 84
y = {{{(- 84)/(- 3)}}}, or {{{highlight_green(28)}}}