Show all work!! 1. Solve by the substitution method. x + 2y = -7 x + y = -3 2. Solve by the elimination method. 3x + 4y =12 2x + 3y = 6 3. Solve by back substitution. x+y+z=1 2y-z=4
4z=8
4. Solve:
x + 6y + 3z = 4
2x + y + 2z = 3
3x - 2y + z = 0
5. Determine the constants A and B using patrial fraction decomposition.
a. x+3/(x+5)(x-1) = A / x+5 + B / x-1
b. -2x + 5 / (x-1)² = A / x-1 + B / (x-1)²