Question
Question: The coefficient of x in the quadratic equation ax<sup>2</sup> + bx + c = 0 was wrongly taken as 17 i...
The coefficient of x in the quadratic equation ax2 + bx + c = 0 was wrongly taken as 17 in place of 13 and its roots were found to be –2 and –15, the actual roots of the equation are-
A
–2 and 15
B
–3 and –10
C
–4 and – 9
D
–5 and –6
Answer
–3 and –10
Explanation
Solution
New roots are –2, –15
Q.E. is (x + 2) (x + 15) = 0 ⇒ x2 + 17x + 30 = 0
correct equation x2 + 13x + 30 = 0
⇒ (x + 3) (x + 10) = 0⇒ x = – 10, – 3
Hence actual roots are –3, –10