7. A= Let 4-[ 4x] 3 8. (a) Determine the | A |= det(A). (b) If | A |= 5, what is the value of x? (4x-y+3z=1 Solve the system of linear equations 3x-2y-z=2 using Cramer's Rule. Be sure to show 5x+y-2z=3 D, D, D, and D. Show you're your computations to determine the solution to the system using the determinants and state the solution as an ordered triple (x, y, z). Use your graphing calculator to evaluate the determinants (do not evaluate by hand). 9. As part of a promotion, a local bank invites its customers to view a large sack full of $5, $10, and $20 gold pieces, promising to give the sack to the first person able to state the number of coins for each denomination. Customers are told there are exactly 250 coins, with a total face value of $1,875. If there are also seven times as many $5 gold pieces as $20 gold pieces, how many of each denomination are there? Please clearly define your variable and write a system of equations for this application. Use Cramer's rule to solve this system.