Unknown g (x) = ax + b and g (g (x)) = 16x - 15. Calculate the value of a and b.

Mathematics · High School · Tue Nov 03 2020

Answered on

For solving this question we take given information by the question 

Given g(x) =ax+b ……..(1) 

g(g(x))=16x-15 ……(2)

For finding the value of “a”and “b” we use equation (1) and solve g(g(x)) substitute value of “g(x)”in “g(g(x))”by the equation (1)

g(g(x))=a(ax+b)+b …….(3) 

 By the equation (2)and(3) both are equavelent to g(g(x)) so we do  equation (2)=(3) 

16x-15 =a^2x+ab +b 

By the comparison of x multiples and constants we get 

a^2=16 

a=√16 or (a)^2=(4)^2

a=4 ans 

And  ab+b=-15 

    b(a+1)=-15

By the putting value of" a "

b(4+1)=-15

b(5)=-15

b=-(15/5)

b=-3 ans