Which of the following statement is true? a. the echelon form of a matrix is unique.
b. the pivot positions in a matrix depend on whether row interchanges are used in the row reduction process.
c. reducing a matrix to echelon form is called the forward phase of the row reduction process.
d. whenever a system has free variables, the solution set contains many solutions.
e. a general solution of a system is an explicit description of all solutions of the system.

c. Reducing a matrix to echelon form is called forward phase of the row reduction process.

Step-by-step explanation:

Forward Phase in Row Reduction Process: It is the process in which operations are performed to get leading entries in non-zero rows.

Backward Phase: It is the process of reducing matrix from echelon form to reduced echelon form.

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

70

step-by-step explanation: