Answer:
3
Step-by-step explanation:
Apply Multiplicative Distribution Law:
{x + y =9
{8x + 24y = 120
Reduce the greatest common factor on both sides of the equation.
{x + y = 9
{x + 3y = 15
Subtract the two equations: x + y - (x +3y) = 9 - 15
Remove paranthesis: x + y - x - 3y = 9 - 15
Cancel the unknown variables: y - 3y = 9 - 15
Combine like terms: -2y=9 - 15
Calculate the sum or difference: -2y = -6
Reduce the greatest common factor on both sides of the equation: y =3
Substitute one unknown quantity into the elimination: x + 3 = 9
Rearrange unknown terms to the left side of the equation: x = 9 - 3
Calculate the sum or difference: x = 6
Write the solution set of equations: {x = 6
{y = 3
Substitute: 6 - 3
Calculate the sum or difference: 3
Answer: 3