Elementary and Intermediate Algebra

Mark Dugopolski, Southeastern Louisiana University

Systems of Linear Equations and Inequalities

Systems of Linear Equations in Three Variables

Warm-Ups


1	The point (1, -2, 3) is in the solution set to the equation x + y - z = 4.
		A)	TRUE
		B)	FALSE


2	The point (4, 1, 1) is the only solution to the equation x + y - z = 4.
		A)	TRUE
		B)	FALSE


3	The ordered triple (1, -1, 2) satisfies x + y + z = 2, x - y - z = 0, and 2x + y - z = -1.
		A)	TRUE
		B)	FALSE


4	Substitution cannot be used on three equations in three variables.
		A)	TRUE
		B)	FALSE


5	Two distinct planes are either parallel or intersect in a single point.
		A)	TRUE
		B)	FALSE


6	The equations x - y + 2z = 6 and x - y + 2z = 4 are inconsistent.
		A)	TRUE
		B)	FALSE


7	The equations 3x + 2y - 6z = 4 and -6x - 4y + 12z = -8 are dependent.
		A)	TRUE
		B)	FALSE


8	The graph of y = 2x - 3z + 4 is a straight line.
		A)	TRUE
		B)	FALSE


9	The value of x nickels, y dimes, and z quarters is 0.05x + 0.10y + 0.25z cents.
		A)	TRUE
		B)	FALSE


10	If x = -2, z = 3, and x + y + z = 6, then y = 7.
		A)	TRUE
		B)	FALSE

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