How do you solve the system of equations 20x + 3y = 2020x+3y=20 and - 20x + 5y = 6020x+5y=60?

1 Answer
Mar 16, 2017

x=-1/2x=12
y=10y=10

Explanation:

20x+3y=2020x+3y=20
-20x+5y=6020x+5y=60

You can add all.

8y=808y=80
y=10y=10

We know that y=10, so we can come back to the one of the first equations. I'll choose 20x+3y=2020x+3y=20.

20x+3*10=2020x+310=20
20x+30=2020x+30=20
20x=-1020x=10
x=-1/2x=12