1.
If you solve the following system of equations by elimination, which of the following is the best choice for the first step?
2
x
+
y
-
z
= 3
x
+
y
+
z
= 5
x
- 2
y
+ z = 2
A.
Neither method will work.
B.
Both methods will work.
C.
Add the first and second equations to eliminate the
z
variable.
D.
Subtract the second and third equation to eliminate the
z
variable.
Hint
2.
Three planes can
A.
intersect in a line.
B.
All of the choices are true.
C.
have no points in common.
D.
intersect at one point.
Hint
3.
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.
You can substitute
x
for
z
into the second and third equations.
B.
Neither method will work.
C.
Both methods will work.
D.
You can substitute
z
for
x
into the second and third equations.
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.
infinite solutions
B.
(1, 3, -4)
C.
(8, 4, -2)
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.
both methods are correct
B.
Method II
C.
neither method is correct.
D.
Method I
Hint