SOLUTION: Solve the system by substitution. 3x – y = –7 x + y = –9

Algebra ->  Algebra  -> Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Solve the system by substitution. 3x – y = –7 x + y = –9      Log On

Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

   

Question 61564: Solve the system by substitution. 3x – y = –7
x + y = –9
Answer by asha(30) About Me  (Show Source):
You can put this solution on YOUR website!
3x-y =-7 eqn.1
x +y =-9 eqn.2
from eqn. we get y =-9-x
plugging the value of y in eqn.1 we get
3x-(-9-x)=-7
3x+9+x=-7
4x =-7-9 =-16
x=-16/4 =-4
but y =-9-x =-9-(-4)
y=-9+4 =-5
the answers are x=-4 and y=-5
good luck !!!