Solve each system in Exercises 5–18.

$\(\begin{cases}\)x + y + 2z = 11 \(\x\) + y + 3z = 14 \(\x\) + 2y - z = 5\(\end{cases}\)$

Determine if the given ordered triple is a solution of the system. $(4,1,2)$

$\(\begin{cases}\)x - 2y = 2 \\2x + 3y = 11 \(\y\) - 4z = -7\(\end{cases}\)$

Determine if the given ordered triple is a solution of the system. $(2,-1,3)$

$\(\begin{cases}\)x + y + z = 4 \(\x\) - 2y - z = 1 \\2x - y - 2z = -1\(\end{cases}\)$

Find the quadratic function y = ax^2 + bx + c whose graph passes through the points (1, 4), (3, 20), and (-2, 25).

Solve each problem. See Examples 5 and 9. The sum of the measures of the angles of any triangle is 180°. In a certain triangle, the largest angle measures 55° less than twice the medium angle, and the smallest angle measures 25° less than the medium angle. Find the measures of all three angles.

Solve each problem. See Examples 5 and 9. Solve the system of equations (4), (5), and (6) from Example 9.

$25x+40y+20z=2200$ (4)

$4x+2y+3z=280$ (5)

$3x+2y+z=180$ (6)

Solve each problem. See Examples 5 and 9. A cashier has a total of 30 bills, made up of ones, fives, and twenties. The number of twenties is 9 more than the number of ones. The total value of the money is \$351. How many of each denomination of bill are there?