Question

Maths f(x) type of question please help

Answer 1

Since 1 < x < 5, adding each side by a, where a is negative, gives

a > ax > 5a

and adding b to each side gives

a + b > ax + b > 5a + b

or

5a + b < ax + b < a + b

Since 7 < f(x) < 23, it follows that

5a + b = 7

a + b = 23

Solve for a by eliminating b :

(5a + b) - (a + b) = 7 - 23

4a = -16

a = -4

Solve for b :

-4 + b = 23

b = 27