Question
Question: In a triangle ABC, ∠A = 60<sup>0</sup>, a = 4 and b = 3, then c is a root of the equation...
In a triangle ABC, ∠A = 600, a = 4 and b = 3, then c is a root
of the equation
A
c2 + 3c + 7 = 0
B
c2 –3c + 7 = 0
C
c2 + 3c –7 = 0
D
c2 –3c –7 = 0
Answer
c2 –3c –7 = 0
Explanation
Solution
cos 600 = 
⇒ c2 –3c – 7 = 0
⇒ choice (4) is correct.