NIMCET 2016 — Mathematics PYQ
NIMCET | Mathematics | 2016Sum of the roots of the equation 4x−3(2x+3)+128=0 is
Choose the correct answer:
- A.
5
- B.
6
- C.
7
(Correct Answer) - D.
8
7
Explanation
Concept:
Base Rule
If b raised to the xth power is equal to b raised to the yth power, that implies that x = y."
bx=by⇒x=y
Calculations:
Given equation is 4x−3(2x+3)+128=0
⇒(22)x−3(2x⋅23)+128=0
⇒(2x)2−24(2x)+128=0
⇒(2x)2−16(2x)−8(2x)+128=0
⇒(2x−16)(2x−8)=0
⇒2x=16 or 2x=8
⇒2x=24 or 2x=23
⇒x=4 or x=3
The roots of the equation 4x−3(2x+3)+128=0 are 4 and 3
Its Sum = 4 + 3 = 7
Explanation
Concept:
Base Rule
If b raised to the xth power is equal to b raised to the yth power, that implies that x = y."
bx=by⇒x=y
Calculations:
Given equation is 4x−3(2x+3)+128=0
⇒(22)x−3(2x⋅23)+128=0
⇒(2x)2−24(2x)+128=0
⇒(2x)2−16(2x)−8(2x)+128=0
⇒(2x−16)(2x−8)=0
⇒2x=16 or 2x=8
⇒2x=24 or 2x=23
⇒x=4 or x=3
The roots of the equation 4x−3(2x+3)+128=0 are 4 and 3
Its Sum = 4 + 3 = 7

