Examples:

1. Find the unique values of variables a and b.

   15*a + 3*b=124.5
6*a + 8*b=77


   

2. Find the unique values of variables a and b.

   3a - 2b = 4.5
a + b = 5.5


   Equation one plus two times equal two yields $$3a-2b+2(a+b)=4.5+2(5.5)\underset{}{\to }5a=15.5\underset{}{\to }a=3.1$$ Plugging the value for a into either equation yields the result b=2.4.