Answer:
c = - 2, c = 7
Step-by-step explanation:
Given
c² - 14 = 5c ( subtract 5c from both sides )
c² - 5c - 14 = 0 ← in standard form
To factorise the quadratic
Consider the factors of the constant term (- 14) which sum to give the coefficient of the c- term (- 5)
The factors are - 7 and + 2, since
- 7 × 2 = - 14 and - 7 + 2 = - 5, hence
(c - 7)(c + 2) = 0
Equate each factor to zero and solve for c
c - 7 = 0 ⇒ c = 7
c + 2 = 0 ⇒ c = - 2
