Answer
$a. 11$
$b. 2a + 7$
$c. -2x + 7$
$d. 2x + 2h + 7$
Work Step by Step
$f(x) = 2x + 7$
$a. f(2)$
$f(2) = 2(2) + 7$
$f(2) = 4 + 7$
$f(2) = 11$
$b. f(a)$
$f(a) = 2(a) + 7$
$f(a) = 2a + 7$
$c. f(-x)$
$f(-x) = 2(-x) + 7$
$f(-x) = -2x + 7$
$d. f(x + h)$
$f(x + h) = 2(x + h) + 7$
$f(x + h) = 2x + 2h + 7$
