Q. 234.0( 1 Vote )

# Mark the correct alternative in the following:If f : R → R and g : R → R are defined by f(x) = 2x + 3 and g(x) = x2 + 7, then the values of x such that g(f (x)) = 8 areA. 1, 2B. -1, 2C. -1, -2D. 1, -2

g(f(x))=8

(f(x))2+7=8

(2x+3)2=1

4x2+12x+9=1

4 x2+12x+8=0

x2+3x+2=0

(x+1)(x+2)=0

x+1=0 or x+2=0

x=-1 or x=-2

Option C is correct..

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Trigonometric Functions - 0568 mins  Trigonometric Functions - 0152 mins  Conditional Identities31 mins  Trigonometric Functions - 0658 mins  Questions Discussion of Biomolecules48 mins  Trigonometric Functions - 0865 mins  Trigonometric Functions - 0760 mins  Master Solving Problems of trigonometry45 mins  Let's Play the Game of Inequalities52 mins  Trigonometric Functions - 0366 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses 