SOLUTION: 17. Solve the system by graphing. 3x + y = –1 9x + 3y = –3

Algebra ->  Equations -> SOLUTION: 17. Solve the system by graphing. 3x + y = –1 9x + 3y = –3       Log On


   

Question 43733: 17.
Solve the system by graphing.
3x + y = –1
9x + 3y = –3


Answer by aaaaaaaa(138) About Me  (Show Source):
You can put this solution on YOUR website!
3x%2By=-1
9x%2B3y=-3
Let's start with the first equation, getting it as a function of y:
3x+=+-1+-+y
3x+%2B+1+=+-y
-3x+-+1+=+y
Second:
9x+%2B+3y+=+-3
9x+%2B+3+=+-3y
-9x+-+3+=+3y
y+=+%28-9x+-+3%29%2F3
y+=+-3x+-+1
Are you sure the equation is right? For any value of x, we can calculate -3x - 1 to get y. See the graph, any point in it is a solution:
graph%28600%2C+600%2C+-6%2C+6%2C+-10%2C+10%2C+-3x+-+1%29