Final answer:
The question involves solving and simplifying expressions related to electrical currents in a physics context, with algebraic manipulations and understanding the properties of exponents playing key roles.
Step-by-step explanation:
The student's question revolves around simplifying mathematical expressions and understanding the methods used for solving equations with multiple currents (I), which appears to be related to circuits. To simplify the given expressions, we perform algebraic manipulation and substitute the known values into equations to solve for unknown currents. The question seems to extract a particular case out of a larger physics problem involving Kirchhoff's rules, which are used for analyzing electrical circuits with multiple loops and branches.
For instance, if we have I₁ = I₂ + 13 = (6 - 2I₁) + (22.5 - 3I₁), we simplify to find the value of I₁. We can check our answer by substituting the values of I₁ and I₃ into another equation from the system of equations given in a physics problem dealing with electrical circuits.
It's also mentioned that the simplification process for exponents, like in 3².35, is similar to multiplying exponents where xPx9 transforms into x(p+q), indicating that the student is dealing with the properties of exponents within their problem.