Assignment:
Solve each system by the substitution method only.
1) x = 9 – 2y
x + 2y = 13
2) 6x + 2y = 7
y = 2 – 3x
3) y = 3x -5
21x – 35 = 7y
4) 9x – 3y = 12
y = 3x - 4
5) 3x – 2y = -5
4x + y = 8
6) 2x + 5y = -4
3x – y = 11
Provide complete and step by step solution for the question and show calculations and use formulas.