TysonBrown
Jan 20, 2009, 03:50 PM
I don't know what to get rid of!
-2x+3y=14
x-4y=-12
Help me!
ROLCAM
Jan 20, 2009, 05:09 PM
-2x+3y=14
x-4y=-12
_______________________
-2x+3y=14
2x-8y = -24
_____________________
eliminate the x's you get:
+3y = 14
-8y = -24
so
-5y = -10
y = 2
x-4y=-12
x = 4y-12
x=8 -12
x = -4
x = -4 and y = 2
sarnian
Jan 20, 2009, 07:17 PM
Rolcam : the student should be helped with an explanation to understand the question and procedure, and answer it himself/herself.
My advice to him/her would be :
Select either x or y, and substitute the value of it in the other term.
The easiest way here seems using x for that.
a) -2x+3y=14
b) x-4y=-12
We know the value of -2x as in term a) is stated : -2x + 4y = 12 , so -2x =...
We know the value of x as in term b) is stated : x - 4y = -12 , so x =...
Divide the value of -2x in term a) with -2 (divide everything with -2), and you get : x =...
Now substitute the value of x from term a) into term b) , and solve y !
This board is called "Homework Help", and not "Do their homework !!!"
shebester
Jan 20, 2009, 07:24 PM
Rolcam you are amazing thanks