Question

How do you solve `5A+7=3A+7+2A`?

Answer 1

`A in RR`

Explanation:

`5A+7=3A+7+2A`

Combine like terms on the right hand side of the equation.

`5A+7 = color(red)(3A)+7+color(red)(2A)`

`5A+7 = color(red)(5A)+7`

`5A+7=5A+7`

The above is a tautology, that is, it is true for any value of `A`. As any value satisfies the given equation, the solution is `RR`, the set of all real numbers.