Step-by-step explanation:
2x + y = 21
Solving
2x + y = 21
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-1y' to each side of the equation.
2x + y + -1y = 21 + -1y
Combine like terms: y + -1y = 0
2x + 0 = 21 + -1y
2x = 21 + -1y
Divide each side by '2'.
x = 10.5 + -0.5y
Simplifying
x = 10.5 + -0.5y
