Question
Question: Let two numbers have A.M. = 9 & G.M. = 4. Then these numbers are roots of equation –...
Let two numbers have A.M. = 9 & G.M. = 4. Then these numbers are roots of equation –
A
x2 + 18x + 16 = 0
B
x2 – 18x + 16 – 0
C
x2 + 18 x – 16 = 0
D
x2 – 18x – 16 = 0
Answer
x2 – 18x + 16 – 0
Explanation
Solution
Let roots are a, b
A = 2α+β ̃ a + b = 2A = 2 × 9 = 18
G = αβ ̃ ab = G2 ̃ ab = 42 = 16
quadratic eqn is x2 – Sx + P = 0
̃ x2 – 18 x + 16 = 0