Solving simultaneous equations using matrices

When a valve is open 281 gallons of water go through it in one hour the number of gallons that would go through in 94 hours is

M? aoc=96 ? space, m, angle, a, o, c, equals, 96, degree \qquad m \angle boc = 8x - 67^\circm? boc=8x? 67 ? space, m, angle, b, o, c, equals, 8, x, minus, 67, degree \qquad m \angle aob = 9x - 75^\circm? aob=9x? 75 ? space, m, angle, a, o, b, equals, 9, x, minus, 75, degree find m\angle bocm? bocm, angle, b, o, c:

How many and of which kind of roots does the equation f(x)=2x^4−9x^3+17x^2−16x+6 have?