Question
Question: If one root of the equation (x – 1) (7 – x) = m is three times the other, then m is equal to –...
If one root of the equation (x – 1) (7 – x) = m is three times
the other, then m is equal to –
A
–5
B
0
C
2
D
5
Answer
5
Explanation
Solution
– x2 + 8x – 7 = m Ž x2 – 8x + 7 + m = 0
a + 3a = 8 Ž a = 2
a . 3a = 7 + m Ž 12 = 7 + m Ž m = 5