A. Elimination method
-6x +18y = -6
6x -3y = -24
15y = -30
y = -2
x = -5
(-5,-2)
B. Elimination method
7x -3y = 20
5x +3y = 16
12x = 36
x = 3
y = 1/3
(3, 1/3)
C . Substitution method
y =x/2 -6
2x + 6y = 19
2x + 6 (x/2 -6) = 19
2x + 3x -36 = 19
5x -36 = 19
5x = 55
x = 11
y = -1/2
(11, -1/2)
Solve using two different methods. Explain which method you found to be most efficient.
A.
3x - 9y = 3
6x - 3y = -24
B.
7x - 3y = 20
5x + 3y = 16
C.
y = 1/2x - 6
2x + 6y = 19
I am just stuck and don't know how to do these last few problems on my assignment. If someone would please help it would be very much appreciated. Thank You.
4 answers
Thank you so much. But I need 2 ways to solve each one, can you show me another method for each.
I will give you the substitution method for b. Then you do a and c
B. substitution method
7x -3y = 20
7 x = 3 y + 20
x = (3/7)y + 20/7
then
5x +3y = 16
5[ (3/7)y + 20/7 ] + 3 y = 16
(15/7)y + 100/7 + 21/7 y = 112/7
36 y = 12
y = 1/3
go back and get x
B. substitution method
7x -3y = 20
7 x = 3 y + 20
x = (3/7)y + 20/7
then
5x +3y = 16
5[ (3/7)y + 20/7 ] + 3 y = 16
(15/7)y + 100/7 + 21/7 y = 112/7
36 y = 12
y = 1/3
go back and get x
Ok. Thank you.