Produces quadratic function
Solution:
Given that
a (x) = 2x – 4 and b(x) = x + 2
Need to check which of the expression from given three expression produce a quadratic function. Let us solve each option and check the result.



So (ab)(x) produces a quadratic function




So (a - b)(x) produces a linear function x – 6.


So (a + b)(x) produces a linear function x – 2.
Hence we can conclude that (ab)(x) produces quadratic function.