1. Solve:-
5x-4y+z=1
3x+6y+2z=2
4x+2y-3z=11.

2. Solve:-
x+y=7, y+z=4, and z+x=1.

3. Solve:-
3x-y=18, 5y+z=-17, and 2z+7x=31.

4. Solve:-

5. In a factory, the wages of 3 skilled workers, 4 security men and 2 casual workers is $350. The daily wages of 4 skilled workers is the same as that of 5 security men. A security man erans twice as much as a casual worker in a day. Find the daily wages of the skilled workers, security men and the casual workers.

6. When 5x³ - 2x + a is divided by (x-2), the remainder is 7. Find a.

7. Given that px³+9x²+qx+1 leaves remainder 4 on division by (2x+1) and 9x³+qx²+px+1 leaves remainder 3 on division by (3x-1), find p and q.

8. Find a and b if x³+7x²+ax+b leaves a remainder 40 when divided by (x-2) and a remainder 25 when divided by (x+3).

9. Find m and n if x³+x²+mx+n is divisible by (x+1)(x+4).

10. Given that (x-1) is a factor of x²+ax+1, show that (x-a) is a factor of x³+3x²+3x+2.