Question 567770
{{{3a-b=5}}} Start with the first equation



{{{3((3/4)b)-b=5}}} Plug in {{{a=(3/4)b}}}. In other words, replace 'a' with {{{(3/4)b}}}



{{{(9/4)b-b=5}}} Multiply



{{{(5/4)b=5}}} Combine like terms



{{{5b=5*4}}} Multiply both sides by 4.



{{{5b=20}}} Multiply



{{{b=20/5}}} Divide both sides by 5 to isolate b.



{{{b=4}}} Divide



Now that we know that b = 4, we can use this to find 'a'


{{{a=(3/4)b}}} Move onto the second equation



{{{a=(3/4)(4)}}} Plug in b = 4 (ie replace b with 4)



{{{a=12/4}}} Multiply



{{{a=3}}} Reduce



So the solutions are a = 3 and b = 4 giving us the ordered pair (3, 4)