Algebra: if 2X - Y = -3, Z - Y = 2, X + Z = 5, find X+Y+Z ?

[stx valley]

Please explain to me how to find this answer.
if 2X-Y=-3
Z-Y=2
X+Z=5
Find X+Y+Z=?

 

[Deleted member 4993]

Re: Algebra

Please explain to me how to find this answer.
if 2X-Y=-3
Z-Y=2
X+Z=5
Find X+Y+Z=?

Observation does not show me any short cut.

Next method would be - three equations, three unknowns - what have you been taught about method of solutions?

for a review go to:

http://www.purplemath.com/modules/systlin4.htm

 

[mmm4444bot]

One way:

Solve second equation for Y.

Solve third equation for X.

Substitute these results into the first equation for Y and X.

Solve for Z.

 

[coloredmath]

2X-Y=-3
-y=-3-2x
y=3+2x

Z-(3+2x)=2
z-3-2x=2
z=5+2x

X+5+2x=5
3x=0
x=0

z=5+2(0)
z=5

y=3+2(0)
y=3

0+3+5=8