Chapter 10: Problem 2
True or false? \(\operatorname{det}(A)\) is a number, not a matrix.
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Chapter 10: Problem 2
True or false? \(\operatorname{det}(A)\) is a number, not a matrix.
These are the key concepts you need to understand to accurately answer the question.
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Use Cramer's Rule to solve the system. $$\left\\{\begin{aligned} 2 x-5 y &=4 \\ x+y-z &=8 \\ 3 x &+5 z=0 \end{aligned}\right.$$
An encyclopedia saleswoman works for a company that offers three different grades of bindings for its encyclopedias: standard, deluxe, and leather. For each set that she sells, she earns a commission based on the set's binding grade. One week she sells one standard, one deluxe, and two leather sets and makes \(\$ 675\) in commission. The next week she sells two standard, one deluxe, and one leather set for a \(\$ 600\) commission. The third week she sells one standard, two deluxe, and one leather set, earning \(\$ 625\) in commission. (a) Let \(x, y,\) and \(z\) represent the commission she earns on standard, deluxe, and leather sets, respectively. Translate the given information into a system of equations in \(x, y\) and \(z\) (b) Express the system of equations you found in part (a) as a matrix equation of the form \(A X=B\). (c) Find the inverse of the coefficient matrix \(A\) and use it to solve the matrix equation in part (b). How much commission does the saleswoman earn on a set of encyclopedias in each grade of binding?
Evaluate the determinants. $$\left|\begin{array}{lllll} a & 0 & 0 & 0 & 0 \\ 0 & b & 0 & 0 & 0 \\ 0 & 0 & c & 0 & 0 \\ 0 & 0 & 0 & d & 0 \\ 0 & 0 & 0 & 0 & e \end{array}\right|$$
Evaluate the determinants. $$\left|\begin{array}{lllll} a & a & a & a & a \\ 0 & a & a & a & a \\ 0 & 0 & a & a & a \\ 0 & 0 & 0 & a & a \\ 0 & 0 & 0 & 0 & a \end{array}\right|$$
Use Cramer's Rule to solve the system. $$\left\\{\begin{aligned} 5 x-3 y+z &=6 \\ 4 y-6 z &=22 \\ 7 x+10 y &=-13 \end{aligned}\right.$$
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