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