Question
Mathematics Question on Application of derivatives
The number of real roots of the equation x2−4x+3+x2−9=4x2−14x+6, is:
A
2
B
3
C
1
D
0
Answer
1
Explanation
Solution
(x−1)(x−3)+(x−3)(x+3)
=4(x−412)(x−42)
⇒x−3=0⇒x=3 which is in domain
or
x−1+x+3=4x−2
2(x−1)(x+3)=2x−4
x2+2x−3=x2−4x+4
6x=7
x=7/6(rejected)