Question

43s² + 18 + 43s² - 31s² - 48s²

Explanation:

Step1: Group like terms

$(43s^2 + 43s^2 - 31s^2 - 48s^2) + 18$

Step2: Combine $s^2$ terms

$((43+43-31-48)s^2) + 18 = (7s^2) + 18$

Answer:

$7s^2 + 18$