Question

What is the solution to this system of equations?

3x+y=30

x−3y=0


(1 point)

(9,3)


(15,−6)


There is no solution.

There are an infinite number of solutions.

Answer 1

From x − 3y = 0, x = 3y. Substitute into 3x + y = 30:
3(3y) + y = 30 → 9y + y = 30 → 10y = 30 → y = 3.
Then x = 3y = 9.

Solution: (9, 3).