Answer:
(g-f)(10) = - 71
Explanation:
f(x) = x² - 1
g(x) = 2x + 8
To find (g-f)(10) first find ( g - f)(x)
To find ( g - f)(x) subtract f(x) from g(x)
That's
( g - f)(x) = 2x + 8 - ( x² - 1)
Remove the bracket
( g - f)(x) = 2x + 8 - x² + 1
Simplify
( g - f)(x) = - x² + 2x + 9
To find (g-f)(10) substitute the value in the bracket that's 10 into ( g - f)(x)
That is
(g-f)(10) = -(10)² + 2(10) + 9
= - 100 + 20 + 9
= - 100 + 29
= - 71
Hope this helps you