1.
The equation 2
x
-
y
+ 3
z
= 5 represents _____________
A.
a plane.
B.
a line.
C.
none of these.
D.
a circle.
Hint
2.
If you solve the following system of equations by substitution, which statement is true?
x
=
z
x
- 2
y
+
z
= 6
2
x
+
y
- 2
z
= 1
A.
Both methods will work.
B.
You can substitute
x
for
z
into the second and third equations.
C.
You can substitute
z
for
x
into the second and third equations.
D.
Neither method will work.
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.
10
B.
8
C.
11
D.
9
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.
no solution
B.
(3, 4, 2)
C.
infinite solutions
D.
(2, -5, 3)
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.
Method II
B.
Method I
C.
both methods are correct
D.
neither method is correct.
Hint