1.
The equation 2
x
-
y
+ 3
z
= 5 represents _____________
A.
a plane.
B.
a circle.
C.
a line.
D.
none of these.
Hint
2.
Three planes can
A.
All of the choices are true.
B.
have no points in common.
C.
intersect at one point.
D.
intersect in a line.
Hint
3.
Solve the system of equations by substitution.
x
=
z
x
- 2
y
+
z
= 6
2
x
+
y
- 2
z
= 1
What is the value of
x
+
y
+
z
?
A.
9
B.
11
C.
8
D.
10
Hint
4.
Solve the system of three equations by elimination:
5
x
+ 2
y
- 3
z
= 10
2
x
- 2
y
+ 4
z
= 6
x
-
y
+ 2
z
= 3
A.
(3, 4, 2)
B.
(2, -5, 3)
C.
infinite solutions
D.
no solution
Hint
5.
If you are solving this system of equations by elimination, which of the following is the best choice for the first step?
2
x
+ 3
y
-
z
= 4
-
x
+
y
+ 2
z
= 3
3
x
+
y
+
z
= 1
A.
neither method is correct.
B.
Method II
C.
both methods are correct
D.
Method I
Hint