Question

Use a system of linear equations with two variables and two equations to solve. A number is 9 more than another number. Twice

the sum of the two numbers is 30. Find the two numbers. Let the two numbers be represented by x and y. Let y represent the
larger number. Write your answer as an ordered pair (x, y).

Answer 1

9514 1404 393

Answer:

(x, y) = (3, 12)

Explanation:

Using the given variable definitions, we can write the equations ...

y = x + 9

2(x +y) = 30

__

Solving the second equation for y, we have ...

y = 15 -x

Substituting this into the first equation gives ...

15 -x = x +9

6 = 2x . . . . . . . . . add x-9

3 = x . . . . . . . . . . divide by 2

y = 3+9 = 12 . . . . substitute into the first equation

The numbers are (x, y) = (3, 12).