Question

Solve: y=3x and x+y=20​

Answer 1

x = 5, y = 15

Explanation:

Use substitution to solve the system of equations.

We'll replace y in x + y = 20 with 3x, since y = 3x.

x + 3x = 20

Combine like terms

4x = 20

Divide by 4 on both sides

x = 5

Now to solve for y (don't forget!)

We'll plug x = 5 back into one of the original equations

y = 3(5) = 15

Check first equation:

15 = 3(5)

15 = 15

Check second equation:

5 + 15 = 20

20 = 20