“If x+y=6 and 4x–y=4 what is the value of x?”

"To solve the system of equations x+y=6 and 4x-y=4 add the equations to eliminate y: (x+y) + (4x-y) = 6 + 4 yielding 5x = 10 so x = 2. Substituting x = 2 into x+y=6 gives 2+y=6 so y=4. This method called elimination is a fundamental algebraic technique for solving simultaneous equations. Such systems are critical in mathematics economics and engineering for modeling relationships between variables ensuring accurate solutions to real-world problems."