Answer:
x = - 5 , y = 0
Step-by-step explanation:
- 4x + 7y = 20 → (1)
y = 3x + 15 → (2)
Substitute y = 3x + 15 into (1)
- 4x + 7(3x + 15) = 20 ← distribute parenthesis and simplify left side
- 4x + 21x + 105 = 20
17x + 105 = 20 ( subtract 105 from both sides )
17x = - 85 ( divide both sides by 17 )
x = - 5
Substitute x = - 5 into (2)
y = 3(- 5) + 15 = - 15 + 15 = 0
Then x = - 5 , y = 0 is the solution to the system
