Name: David Dean
Who is asking: Other
Level: All

Question:
2a + 1b = 3.39 3a + 3b = 6.59
What formula do I use to find what a = ?

Not a formula but I can show you a process that you can use. One way to find a is to find a way to eliminate b. In the first equation the coefficient of b is 1 and in the second equation the coefficient of b is 3. Hence, if you multiply both sides of the first equation by 3 then, in both equations, the coefficient of b will be 3. The equations are

Subtracting the second equation from the first equation gives

Solve for a.