Question

PLEASE HELP!!!! ):
x+y+z=6
x=2y
z=x+1
Solve the system of equations...
The answer should be (2,1,3) but im so confused on this lesson. Can someone PLEASE help!

Answer 1

You have a system of three equations in three unknowns, x, y and z.

Why not keep the variable x and eliminate the other two variables, y and z?

If x = 2y, then y = ? You could substitute this result for y in the first equation.

z=x+1. substitute this result into the first equation.

Then solve the re-worked first equation for x. Next, find y and z.

Answer 2

x = 2y
z = x + 1

x + y + z = 6
2y + y + x + 1 = 6
3y + x + 1 = 6
3y + x = 5
3y = -x + 5
y = -1/3x + 5/3

x = 2(-1/3x + 5/3)
x = -2/3x + 10/3
x + 2/3x = 10/3
3/3x + 2/3 = 10/3
5/3x = 10/3
x = (10/3) / (5/3)
x = 10/3 * 3/5
x = 30/15
x = 2

x = 2y
2 = 2y
2/2 = y
1 = y

z = x + 1
z = 2 + 1
z = 3

Answer 3

mathmale's way sounds easier

Answer 4

i get it now! thanks!!! i was having trouble knowing which equation to start with and how to proceed!

Answer 5

Can you help me with another section??