Question

- 7x - 5y = 36
x = 2y + 3

Answer 1

Solution

`x = - 3,\: y = -3`

Explanation:

If the objective is to solve for the system of equations
- 7x - 5y = 36 [1]

x = 2y + 3 [2]

Then the process is as follows

• Substitute x = 2y + 3 from eq [2] in eq [1] : -7 x- 5y = 36
  ==> - 7(2y + 3) - 5y = 36
  
• Expand the brackets
  -7 ( 2y + 3) = -7 (2y) - 7(3) = - 14y - 21
  
• Simplify
  ==> -14y - 21 - 5y = 36
  ==> -19y - 21 = 36
  
• Add 21 both sides:
  -19y -21 + 21 = 36 + 21
  -19y = 57
  
• Divide both sides by - 19
  - 91y/-19 = 57/-19
  y = - 3
  
• Substitute y = -3 in x = 2y + 3:
  x = 2(-3) + 3 = -6 + 3 = -3
  x = -3